Tim is placed on the Teacher of the Year selection committee.

Martin's latest machine effects a mind swap with Mrs. Brown.

In a department store, Martin is frozen into a mannequinlike pose.

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.

A short circuit in Martin's transmitter puts him and Tim on nationwide TV.

Tim diverts Mrs. Brown's attention while Martin returns the spaceship to the garage.

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.

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.

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.

Mrs. Brown's niece, Paula Clayfield, comes for visit. A former child prodigy, Paula has always relied on her brains to mask insecurities in her personal appearance. Despite her Plain Jane looks, Paula does have a boyfriend, Dr. Edgar Edgarton (her intellectual equal), with whom she has an "understanding" - they have a commitment to each other shy of a formal engagement. Paula notices Martin's sketches for a space ship, and insists on helping him to refine his design. Later, she also notices in Martin's possession a piece of a Martian alloy (something not available on Earth) to which she states she cannot identify its contents. These probings of course hinder Martin's progress in fixing his space ship as well as his hiding his Martian identity, so Martin asks a reluctant Tim to ask her out to keep her otherwise occupied. After Paula and Tim's first "date", Paula confides to Martin that Tim seems disinterested, which is indeed the case. So to get Tim to ask Paula out again, Martin transforms her into a ravishing beauty without her knowledge. This transformation does the trick on Tim, who continues to take Paula out and eventually asks her to marry him, which convinces her that she can be and is beautiful. Edgar comes for a visit, and after some time he notices the transformation in her appearance, which solidifies their commitment to each other. In the meantime, Paula has accidentally taken Martin's alloy, which she and Edgar are going to get tested. Martin's Martian identity would then be exposed, that is unless Martin and Tim can get the alloy back beforehand.

Martin's present to Tim: a memory machine.

Martin can't decide whether or not to return to Mars.

Martin's duplicating machine creates another Mrs. Brown.

To prove that childhood is unnecessary, Martin adopts an orphan girl.

On Martian Mother's Day, Martin spots his mother's lookalike.

Tim accidentally gets mixed up with a fleeing secret government agent who is involved with a deadly organization called CRUSH. This leads Tim to go undercover with Uncle Martin by his side helping him stay out of trouble.

One of Martin's odd gadgets makes Mrs. Brown two-dimensional.

Tim's I.Q. soars when he downs Martin's brain-power pills.

Trouble begins when Tim contracts a Martian virus.

Martin's personality altercator turns Mrs. Brown into a thief.

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.

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.