Reporter Tim O'Hara, while covering a flight of the Air Force X-15, finds a spaceship that contains a genuine martian. The martian is a professor who specializes in the planet Earth and now has to repair his spaceship before he can go home.

There is dual girl trouble in the O'Hara household. George, the dog who Tim is looking after for Mr. Burns, is in love with Chloe, the dog from next door. Through trying to get George and Chloe together, Tim falls for Chloe's owner, Marsha Carson. However Marsha has had some recent relationship problems of her own. Howard Loomis, her boyfriend, took off to Mexico without as much as a goodbye. Because Marsha feels betrayed by Howard, she is now overprotective of Chloe and suspicious of all men, including Tim. Tim's case is not helped by Angela, who bad mouths Tim to Marsha solely because Angela has a crush on Tim herself. From information from Chloe, Martin finds out the whereabouts of Howard, who rushes back to Los Angeles based on "anonymous" information provided by Martin. Howard, whose departure to Mexico was beyond his control and who tried to contact Marsha prior to his departure, clears the air with her and reignites their relationship to the point of getting engaged. This leaves Tim out in the cold. But at least all works out for George and Chloe, as Tim is given the task of sitting for Chloe while Marsha and Howard rush off to Las Vegas to get married.

Martin comes down with a common cold, which is not so common but rather debilitating for Martians. Meanwhile Tim is sent to Trimbles Department Store to review their outer space exhibit. Trimble, a major advertiser in The Sun, tries to buy and bully for a good review, despite the display showing every unfounded stereotype of life on other planets. Tim knows the display to be total fantasy. But he doesn't get a chance to write the review as he inadvertently takes one of Martin's sleep inducing cold tablets and falls asleep. To submit the review by deadline, Martin writes the review based on his own personal experience of what is true to life on Mars. Trimble is livid and wants Mr. Burns to fire Tim unless Tim apologizes and writes a retraction; Mr. Burns is willing to do so. Tim is going to do as Trimble and Burns wants if only to keep his job and keep from financial bankruptcy, but Martin doesn't want him to compromise what he knows to be right and wrong. Tim does stand up to Trimble and Trimble keeps to his threat until Trimble's usually mild mannered daughter, Gloria, takes her cue from Tim's moxie and stands up to her father about the quality of the exhibit. Trimble changes his tune as he admires the stand up quality of his daughter.

Martin reads about a $2 billion American space program, a program he knows is doomed for failure. Not wanting to see the American government waste $2 billion, Tim writes himself a fake letter to the newspaper which includes Martin's nighttime musings; Tim thinks Martin's mumblings are key to the flaw in the space program. Based on the fake letter, Tim writes a newspaper story criticizing the wasted $2 billion. Tim's masquerade is uncovered by the government, agents for whom think he's a spy working for the Russians. Tim is questioned under a lie detector, and he fails miserably when it comes to questions about Martin. So the agents call in Martin, the agents who question him under the lie detector, under hypnosis, and through brainwashing. Martin overcomes each, to him, primitive method. But he can't overcome the truth serum, and he spills the beans about being a Martian. It isn't until then that the agents let Tim and Martin go. They figure that Martin is crazy and delusional, which is causing stress on Tim which in turn made him write the letter.

Renowned scientist Professor Newton Jennings posits that life no more advanced than amoebas or jellyfish can exist on Mars. Martin helps Angela write a report refuting Jennings claims, which quickly gets her a failing grade. When Martin's attempts to reason with Angela's teacher fails, Martin figures the only way to regain the upper hand—and Angela's trust—is to expose Jennings as a fraud.

To get some rarefied air, Martin goes atop a water tower. Passersby, including the police, think he's a jumper and he's promptly sent to the psychiatric ward of the hospital. Martin thinks he can quickly exit the hospital by reading the psychiatrist's mind and tell him what he wants to hear. However the psychiatrist, Dr. Harvey Bonnett, has other things on his mind, like his troubled marriage. Ultimately, Dr. Bonnett becomes the patient and Martin the doctor.

Martin allows himself to experience an emotion foreign to Martians: love at first sight. He falls hard for Peaches Ancream (Kathie Brown), that being her real given name since her father had a sense of humor. It is also an appropriate name as she is an exotic dancer. Peaches and Martin hit it off, so much so that Martin wants to marry her after their first date. Peaches admires honesty more than anything else in life, the reason that she broke up with her last boyfriend, Police Officer Thorp, who is still harboring strong feelings for Peaches. Martin decides to tell Peaches the truth about himself, which Peaches doesn't believe. When Officer Thorp confesses about the reason for his lies - he told her 6 different places where he was from since in reality he is an orphan who doesn't know - Peaches goes back to the man she feels is being more truthful.

Tim talks Martin into temporarily giving him a Martian power. Martin decides to give him the power of levitation for a 24 hour period. When he thinks the power practically useless beyond performing mere parlor tricks, Tim asks for another, to him, more useful power: mind-reading. Martin grants him his wish, to be activated the next day and to last until midnight. Tim also uses this power for parlor tricks, which gets him into trouble. But he also wants to use it for an interview he has that afternoon with Councilman Jack Gramby. Tim wants to write a story about the Councilman's true political intentions. Tim is unable to read his mind because the Councilman is uncommitted in his political intentions, even to himself. So Tim writes a story on what he calls the mental ping-pong of the Councilman. The Councilman telephones Mr. Burns, Mr. Burns thinking that it is to sue the paper for libel. Distraught about probably losing his job, Tim goes into hiding for the rest of the day. However when Mr. Burns finds Tim just before midnight, he tells Tim that Gramby actually wanted to congratulate the paper. Reading the story made Gramby realize that he as a politician really did need to take a stand. Mr. Burns wants Tim to do such an exposé with all politicians at City Hall. Unfortunately Tim's mind-reading powers are just about to run out.

When the junk men come by, they mistakenly empty Martin and Tim's garage instead of Mrs. Brown's, and in doing so take Martin's space ship. Mrs. Brown has no idea the name of the junk yard, but there was a witness to the incident: Booboo, a neighborhood dog. Booboo, with the help of his dog friends and acquaintances, helps Martin track down the junk yard. When Martin and Tim get to the junk yard, they find out that the ship has already been sold to a Mr. Carter, who is using it as a "rocket" carousel at a children's amusement park. Mr. Carter refuses to sell it back to Martin. So Martin decides to disappear and fly the spaceship away, although he does slip Carter the money for the ship anonymously. Martin has one other debt to pay: a steak dinner for Booboo and all his friends for all their help.

When Martin almost gets a parking ticket, Tim thinks it might be a good idea if Martin legitimizes his Earthly driving by getting a driver's license. Down at the Department of Motor Vehicles, finger-printless Martin has to do some fancy work when he is about to be finger printed. He steals the prints of another man at the DMV. Unfortunately for Martin, that print matches the only unidentified print at a major jewel robbery the previous year. In a routine cross check, the police find the print in Martin's file. And Tim covered the jewel robbery for the paper, something the police find probably more than just a coincidence. Martin and Tim find out that the police are watching them and the reason, and so Martin thinks it a good idea to flush out the jewel thief: he reads that there is a party where Mrs. Summer Winthrop will be displaying the galaxy diamond necklace around her neck, a lure too irresistible for the thief. At the party, the guests are populated predominantly by police - both in uniform and under cover - and the thief, Brian Henley, and his female accomplice, who Martin recognizes from the DMV office. Henley manages to slip the necklace off Mrs. Winthrop, slip it to his accomplice, who in turn slips it into the crown of the cap of Captain Farrow, the lead police investigator. Henley plans to steal the necklace back after the place has been unsecured, and he is no longer a suspect (he was the only person close the Mrs. Winthrop when the necklace went missing). Martin, seeing where the necklace was stashed, plans to plant it back on Henley. No matter what Henley does to get rid of the necklace Martin plants in his pocket, he is no match for Martin's levitation finger. Henley is quickly apprehended, and Martin and Tim cleared.

Martin needs the hardest substance possible to repair his spaceship, the substance he has in mind is silibalt, an alloy of silicone and cobalt but one that has not yet been invented on Earth. To make some, he needs a cyclotron. Rather than destroy Tim's kitchen making his own, he decides to follow Tim on his latest interview at the university, where there is a cyclotron. At the university, Martin meets Tim's interview subject, Donald Mumford, 13-year old physics genius, and one who is constantly at odds with the ways of Dr. Jackson, his advisor. While Martin and Donald get together to discuss and proceed with the making of silibalt, Tim is preoccupied with Dr. Jackson, who provides a diatribe against the demands of Donald, and Jeanine Carter, Dr. Jackson' pretty assistant and university protector of Donald. They are all looking for Donald and Martin when an explosion caused by some stolen electricity and wrong switch alert them to the Donald and Martin's whereabouts. Dr. Jackson immediately expels Donald, and since no long lasting physical damage was done, only banishes Martin from the university. Martin however fights back and convinces Dr. Jackson that he is quashing a genius mind, albeit one in a 13-year old body, and thus Donald must be treated differently in every respect. Doanld is welcomed back. On his own, Donald does manage to make some silibalt for Martin. Martin's only problem now is that he has no instrument hard enough to cut or mold the silibalt.

Tim is pursuing who seems to be the unattainable Cynthia Parker. Through reading her mind, Martin finds out that Cynthia is passionate about the classical arts whether it be music, literature or art, and she figures Tim is not, which is the truth. However Tim becomes everything she wants in a man. However this façade Tim fears is hurting Cynthia. Rather than hurt her by telling her the truth, he decides the best option is to find her her dream man. To do so, Martin needs to read men's minds to match them up to Cynthia's. Scanning through Tim's office, they find one perfect match: Bill Fisher. As perfect as Bill would be, there is one catch: he is already seeing someone he nicknames "Angel Face". Peggy Collins, aka Angel Face, is however as well suited to Bill as Cynthia is to Tim. As a matter of fact, Peggy is better suited to Tim and Cynthia to Bill. At a concert that evening at which all four are scheduled to attend, Martin does a little levitation of tickets so that Bill and Cynthia sit together and Peggy and Tim sit together. Each respective pair hit it off. A month later, Bill and Cynthia get married. Things for Peggy and Tim are also going well, however Tim is a bit freaked when Peggy catches Cynthia's wedding bouquet.

The O'Hara's have new neighbors, the Richmonds, within the family being young Stevie and his grown up sister Jennifer. The foursome go on a picnic to Sunset Mountain, since Martin needs to pick up some bling, an alloy located there but that has not yet been discovered by humans. Stevie has a vivid imagination and likes to pretend he's from Mars, which intrigues Martin. That's OK with Tim, as that means he can spend time with Jennifer alone. However Jennifer is concerned with Stevie's ability to discern reality from fantasy. While Martin goes off to collect his bling, Stevie plays a game of pretend and climbs up the mountain, but reality hits when he can't get down on his own. Martin suggests that Tim climb up and get Stevie as an act of heroism, but Tim is afraid of heights. Martin reassures Tim that he will be safe with the assistance of his remote control gravitation machine. Tim bounds up the mountain, but doesn't know that Martin's machine breaks while he's half way up. Tim and Stevie have a couple of close calls, which Tim thinks is Martin just trying to be dramatic. Although Tim faints when he finds out the truth about the gravitation machine, he shows that one just needs to have a little faith to accomplish mountains.

Tim's cousin Harvey is coming for a visit, which means Martin is going to have to go into hiding since Harvey would know that Tim has no Uncle Martin. And they have to keep Mrs. Brown away from Harvey since she would definitely spill the beans about Martin. Living in a small apartment, Martin can only keep away from Harvey so much, even if he is in his invisible state. And the sleeping arrangements become an issue. Those are not the only problems about Harvey's visit: Harvey is the biggest mooch in the world. Harvey wants Tim to help him get a job at The Sun as Harvey sees himself as the greatest newspaper writer in the world. Tim reluctantly does get Harvey a try-out in a position at The Sun. When Harvey mentions the high stress of this new job, Martin has an idea: he comes by the apartment posing as an old hard-boiled newspaper buddy of Tim's looking for a job. He mentions that he is looking for work on a small town paper, where newspaper life is more rewarding as high stress jobs, like the one Harvey currently has on The Sun, causes one to see things. That's when Martin starts moving things with his levitation finger, causing Harvey to think he's stressed out from his new job. He quickly returns home to his old job.

The stupidest idea Martin has heard of since he's been on Earth: Rosemary Willis leaving her cat, Max, $650,000 in her will. Morton Beanbecker, the lawyer for the estate, is threatening Tim with a lawsuit if he continues to editorialize about the stupidity of the will and deceased Rosemary Willis. However, Beanbecker also mentions that Mrs. Willis wrote a subsequent will leaving her estate to a children's orphanage, that will which was either never signed or hidden. Martin reads his mind that he really wants the second will to be found despite his threatening words to Tim. Tim and Martin find out that Max's trustees are Rosemary's sister, Aggie, and Aggie's husband, Charles. As Aggie and Charles are lavishing money on Max and themselves in the process, Martin and Tim think Aggie and Charles hid the second will. However Max tells Martin himself that he is miserable with all the money, and it was he himself who hid the second will only because Rosemary did forget to sign it. Max leads Martin to the will. Beanbecker and Martin pour through legal books to find precedent to overturn the first will, without success. As Aggie says she hears from Rosemary in her sleep, they decide to hold a séance, where Rosemary - really Martin - will tell Aggie that she wants the money turned over to the orphanage. The ever obliging younger sister Aggie does as she's told.

Martin can make it back to Mars since Mars has deviated from its regular orbit temporarily and is thus closer to Earth than usual. Martin has a 10 hour window of opportunity. Just as he is about ready to leave, he slips down the stairs and sprains his ankle, which also sprains his disappearing antenna. Mrs. Brown immediately calls an ambulance to the scene. When the ambulance physician takes Martin's vital signs, they rush him to the hospital since his vital signs aren't "human". The intern at the hospital has the same reaction. Martin knows that to get them to discharge him from the hospital, he needs to appear humanly normal and thus does everything he can to have normal human vital signs. He passes that test, but when the doctor requires a fluoroscope, Martin is worried since the gamma rays from which will make him explode. Tim manages to take the fluoroscope for Martin, but the doctors keep Martin in the hospital to figure out why the fluoroscope shows that he has the body of a 20-year old. With one hour to spare, Martin regains the use of his disappearing antenna and manages to escape from the hospital. Just as he is ready to leave Earth for the second time, Martin slips down the stairs once again and sprains his other ankle. Nothing can help him this time and he misses his opportunity to get home to Mars. But Martin surmises that home is where you hang your hat, and that just happens to be Earth for the time being.

Something is causing Martin's metabolism to go haywire. In succession, he loses control of his levitation finger, he magnetizes his clothing, he levitates, he becomes electrically charged, he shrinks and then he disappears. He finds out the cause is an increased activity of sunspots, and on Earth there is no way to control their effects on Martians. After five days, the sunspots are still occurring and Martin is still invisible. The authorities, based on a recent insurance policy Mrs. Brown sold Martin with Tim as beneficiary, suspect that Martin's "disappearance" is due to Tim killing him for the insurance money. Circumstantial evidence points in that direction. Martin can't let Tim go to jail for this, and Martin decides to tell the authorities the truth about his Martian identity. Just then, the sunspots cease and Martin reappears, just in time to save Tim and protect his own identity.

Martin and Tim are on their way to interview Professor Eugene Downey, the foremost expert on rocket fuel - Martin thinks the professor can assist in getting him back to Mars - when Martin is hit on the head with a monkey wrench. Martin gets amnesia from this concussion. He has no idea that he's a Martian, despite Tim telling him so. The only thing Martin and Tim can agree on is that Martin needs to go see a doctor. At Dr. Gilbert's office, Martin does learn that he has the power of levitation and the ability to disappear, still not quite believing why. The doctor, who witnesses the levitation, is told it's all magic. Back at the apartment, Tim almost has Martin convinced of his true identity when Martin is once again struck on the head, this time by a hammer. That's all he needed as he regains his memory. It's too late however: Professor Downey has already left town for good.

At the museum, Martin discovers that the long-time curator, Wilbur Canfield, is very unhappy. He has just acquired a new expensive Egyptian piece for the museum, but the museum's board is questioning the authenticity and therefore merit of this acquisition. Because of this, Canfield himself is now questioning his own abilities, as he feels he may be getting too old to do his work properly. The board is calling in an independent expert, Pietro Donati. What's worse, Canfield once discredited Donati's evaluation. Martin will know the piece's authenticity, if he can only get a look at it. In doing so, Tim can get an exclusive story and Martin can validate Canfield as an expert in the field. But the artifact is stashed away behind security until Donati's arrival. Since Martin can't get close to it, he decides instead to levitate it to him. After Martin finds that it is indeed authentic, he has to get it back to the museum. However security is aware that it's missing and thus the museum is secured even more than usual while they try to locate the artifact. After some tricky maneuvering, Martin does manage to get it back into place, although to the bewilderment of security. However, Martin forgot to check for the mark of Ra, which definitely identifies the artifact as authentic. When Donati arrives to inspect the piece, he deems it to be a fake since the mark of Ra is not there. However Martin tells him to look a little more closely under the couple thousand years of residue. The mark is indeed there. Therefore it ends well for Canfield and Donati. The only person with an unhappy ending is Tim - his exclusive story was so good, Mr. Burns appoints him editor of culture, which is not exactly his cup of tea.

Martin wants to help Tim with the household expenses, and without a money earning activity, decides to sell art he's currently painting to relive boredom. Martin can paint in the style of any famous artist. Mr. Green of the Green Gallery notices Martin's first piece is just like a Van Gogh, and eagerly takes and sells it. As such, Mr. Green commissions Martin to paint some more and they sell as quickly as Martin gets them to the gallery. Mr. Green wants to have a showing of Martin's work. When Tim mentions that this might not be a good idea as it may raise questions about Martin himself, Martin offers Tim up as the true artist of the paintings. At the show, Mr. Bentley, the art expert brought in the evaluate the show, is skeptical that Tim painted all the paintings, since they are all in different styles. Mr. Green suggests that Tim provide a real life demonstration of his painting process. Martin assures Tim that with his help, he can indeed paint. However, when Tim's demonstration is supposed to start, Martin has an allergic reaction which is affecting his Tim-assisting painting finger. Martin has to find out what he's allergic to and get rid of the item. Tim is nervously on his own until Martin finds the allergy inducing source. Martin discovers the source is a corsage worn by Mrs. Bentley. Martin manages to get rid of the corsage, and Tim, with Martin's help, proceeds with his painting demonstration to great fanfare. Mr. Bentley deems Tim a major art talent. However Martin announces that Tim has given up on emulating the masters, and will strike out as an artist on his own merit and own style. As such, Tim is a failure. Tim's art career is over, much to his relief.

The Inter-Galaxy Corporation is launching a rocket to either Mars or Venus. Martin needs to convince them to choose Mars, so that he can stowaway and get home. J.M. Buckley, Inter-Galaxy's President, is an indecisive man, but is highly superstitious and makes many decisions on these superstitions. He is leaning toward sending the rocket to Mars, but two things are distracting him from making the announcement of such: it's Friday the 13th, and he's missing his lucky rabbit's foot. Martin overcomes the date superstition by making Buckley think that Friday the 13th is the luckiest day on the calendar. The missing rabbit's foot on the other hand Martin and Tim need to find. They locate it, but in cat-chewed state. Martin realizes that many rabbit's feet look similar and he uses his powers to recreate it to its original visual state. That's all Buckley needs to make the announcement to send the rocket to Mars, the launch to take place in two days. To thank the corporation, Martin suggests adding a magnetic oscilloscope, an invaluable piece of equipment for the mission, to the rocket. This act of kindness on Martin's part is also his error: with the addition of the oscilloscope, there is no more room for a stowaway.

Tim discovers that Martin's antennae can pick up radio and television signals and other things. While Martin's asleep, Tim tunes him into a police frequency hoping for a newspaper scoop.

After Martin makes Tim miss a deadline, Martin decides to help Tim get an exclusive interview. Jakobar, the rogue leader of Kobima, is the story's subject matter. Martin is a legend in Kobima and has inside knowledge of Kobiman legend since he was good friends with Jakobar's great-grandfather Kobima, for who the country was named. After displaying the sign of Cocobahn - Martin's name in Kobiman - Jakobar agrees to see Martin. Martin talks Jakobar into making himself accessible to the media, namely Tim, but later reneges since he still has the suspicious mind of an outlaw leader. Martin needs to convince Jakobar to be a more forthright leader for the betterment of Kobima, which will perish as a country otherwise, this strategy which again includes being accessible to the media. Because of Martin's sage advice, Jakobar muses that Martin may actually be Cocobahn.

Mrs. Brown is taking a course on how to be a private detective, and her first assignment is to prepare a dossier on an unsuspecting person. Her choice of subject is Martin. Of course, Martin knows what she's up to, but he is still a bit concerned about her discovering his Martian identity. Mrs. Brown finds Martin's flight log, which is written in Martian, but again Martin is concerned since the uneducated are too dense to know any better. She takes a photograph of it, which Martin is worried she will pass onto authorities, who, when they are unable to decipher it, will suspect him of being a foreign spy. She apparently has mailed the film to her teacher, J. Nathaniel Pierce, who is more shyster than teacher. Martin needs to apprehend the film before Pierce gets a hold of it. At Pierce's office, Martin searches to no avail, and must endure a sales job by Pierce before he finds out that the mailman can't and won't deliver Mrs. Brown's film since she failed to put postage on the package. From there, it's a an easy task of levitation for Martin to get the film and ultimately protect his identity. For Mrs. Brown's own safety, Martin tries to talk her out of taking the course since she will be facing brutish criminals. She heeds his advice: instead of quitting the course however, she decides to protect herself by also taking judo lessons.

Pete Dudley, a real estate salesman, convinces Mrs. Brown that she should sell her ramshackle of a house, which causes a problem for Tim and Martin, especially in hiding the spaceship. Dudley already has prospective buyers, Edgar and Emily Graham, who would be especially interested in the garage since Mr. Graham wants to make it into a workshop. When the Graham's show up unexpectedly for their first visit, Martin has to hide the spaceship. The only thing he can do is to levitate it with his levitation finger, which even for Martin is difficult due to the ship's large size. They manage to hide the ship long enough for the Graham's visit. Dudley makes Mrs. Brown sign a contract for a $100 advance in commission. After doing so, Mrs. Brown is having second thoughts about selling the house. Martin decides the best avenue to take would be to show the Grahams and Dudley just how ramshackle of a house it is, which he does of course with a little help of his Martian powers. As such, Dudley not only loses the sale, but the Grahams as clients. Martin also gets Mrs. Brown's $100 back for her. And as for Dudley, he decides to leave the real estate game due to some frayed nerves.