Peter Cole is caught one night sleepwalking with a letter opener and standing over his wife's bed. His wife Doris is afraid and decides the next day to file for divorce. Exactly one year later, when the divorce is to be finalized, Frank Maddox, Peter's business partner, meets with Doris Cole. Together they arrange to force Peter Cole to pay Frank Maddox $500K to buy his share of the business or Doris will stop the divorce that Peter wants. That night Frank Maddox spends the night at Peter Cole's house and exchanges bedrooms with Phillip Kendall, Peter's stepbrother. The next morning Phillip Kendall is found dead in bed and Peter Cole is accused of murder due to his known sleepwalking.

Sybil Granger hires Perry to help her buy stock in her estranged husband's oil company on the sly. By this, Sybil hopes to force her husband's latest girlfriend, Roxy Howard, out of the company and his life altogether. Things get complicated when George Lutts enters the picture and gets shot to death.

Donald Briggs is an unscrupulous private investigator hired by Clyde Waters to uncover information about Marv Adams, his daughter's fiance. Briggs learned that Marv Adams' father was Ben Devereaux who was convicted of murder 18 years ago. Donald Briggs is trying to blackmail Clyde Waters and Martha Norris in return for keeping silent about certain facts regarding the Devereaux case. The next evening Donald Briggs is found dead in his motel room and Marv Adams is accused of the murder because he had a fight with Donald Briggs the previous morning.

Fran Celane feels her uncle, Edward Norton, is too restrictive as the executor of her father's spendthrift trust. He also wants her to wait 18 months until her 25th birthday before she gets married. Arthur Crinston, Edward Norton's attorney, arrives to meet with Mr. Norton but is told to return at 11pm. When he returns, they meet for a few minutes and as he is leaving, Mr. Norton asks him to take his secretary, Donald Graves, to pick up some papers. As they drive away, Mr. Graves looks back at the house and sees someone attack Edward Norton. They return to find Edward Norton dead and Rodney Gleason, Fran's fiance, is identified as the assailant. Rodney Gleason is accused of the murder.

Harry Marlow owns a florist business and wants to own a part of Mildred Kimber's orchid business but Mildred Kimber is not interested. So Harry Marlow makes an arrangement with a local club owner, Sam Lynk, to cheat Mildred's husband, Bob Kimber, out of his share of the business in a card game. Meanwhile an employee of Sam Lynk, Lola Florey, decides to help Mildred Kimber to get the shares of stock back from Sam Lynk. When Sam Lynk is found dead in his home, Mildred Kimber is accused of the crime after her prescription drug container is found in Sam Lynk's house.

Hollywood producer John Addison picks up an attractive young woman hitchhiker. Far from being innocent she turns out to be a blackmailer and a witness to a murder that Addison is charged with. Perry, as usual, is hired to get to the bottom of things.

Ed Davenport learns that a sandwich he requested to be tested by a lab contains arsenic and blames his wife Myrna. When he confronts her about his suspicions she denies it. He leaves for a business trip and falls ill. Dr. Renault is called to treat him at a motel where Ed Davenport later dies. Before he dies he claims his wife poisoned some candy. After locking the motel room the doctor calls the police. The police arrive to find the corpse missing. The police test the candy and indeed find arsenic. Subsequently Ed Davenport's body is found in a shallow grave. Myrna Davenport is accused of the murder.

Perry Mason and Paul Drake are on a fishing trip when they spot a young woman named Sally Fenner being pursued by vicious guard dogs on an island estate. The only way Sally can avoid being chewed up by the dogs is to jump into the water and swim for it. Perry and Paul pull Sally out of the drink and Perry ends up defending her on a murder charge.

Restrauteur Morey Allen, a friend of Perry and Della's, has a problem: his waitress, Dixie Dayton, was struck by a car while fleeing the restaurant after spotting a man stalking her. The only item she left behind was a moth-eaten mink. When the stalker is found murdered, Morey and Dixie are both strong suspects and eventually get arrested for the murder. The case also ties in with the murder of a young policeman several months before.

Robert Dawson confronts Albert Tydings, his partner, about $80K missing from Carol Stanley's trust account. Albert Tydings admits he embezzled the money and blackmails Robert Dawson to keep quiet or he will reveal some scandalous facts about Carol. Later, Carol calls and makes an appointment to meet Albert Tydings at his office to discuss the trust account. She arrives to find Albert Tydings dead. The next morning Perry goes to Albert Tydings' home and finds him there dead. Eventually the police determine Tydings body was moved from his office. The police accuse Carol Stanley when her car is reported seen at the office at the time he was murdered.

Perry and Della witness an automobile accident which leads Perry to defend an exotic dancer charged with murder.

Nadine Marshall lives with her Uncle Martin and Captain Hugo. She comes home excited with the news of her engagement to John Locke. When she tells her Uncle Martin, he shows her some papers about her family which upset her. When Nadine visits John Locke, she takes some cyanide pills without John noticing. Later that evening Nadine makes her Uncle Martin's nightly hot chocolate and he dies shortly afterward. Nadine is accused of murder when she makes a taped confession that she killed her uncle.

Arlene Dowling reports the theft of all her belongings, including a diary she is anxious to get back.

Perry has to navigate his way through a hornet's nest of murder, hit-and-run, secret marriage, and a missing witness in this episode.

Claire Olger is hitchhiking because her purse was stolen at the bus station and is picked up by Michael Greeley. He loses control of the car and has an accident due to his being intoxicated. Arriving at the scene of the accident, the police find Claire in the driver's seat. The district attorney's office questions her but do not believe her story about another driver. Her friend, Doris Stephanak, asks Perry Mason to help. When Perry is unable to contact Claire at her hotel, he goes there and finds Michael Greeley dead in her room. The police accuse Claire Olger of murder, realizing Michael Greeley fits the description of the man she claimed was driving the car and believe she had motive and opportunity.

Heiress Marilyn Cartright places an ad in a magazine in order to find love and companionship. In reality, Marilyn is looking for the con artist who swindled and drove her sister to suicide. Marilyn eventually finds the man, Charles "Country Boy" Barnaby, and turns on her ample charm in his direction hoping to get the goods on him. But when Barnaby is found poisoned to death the police theorize that Marilyn killed him as an act of revenge.

Arthur West, a disreputable private investigator, has found J. J. Stanley in a cheap motel. He knows Mr. Stanley and his partner Ned Bain were involved in the embezzlement of the Texas National Bank. He wants to blackmail Ned Bain into giving him money to keep quiet. Harriet Bain, Ned Bain's daughter, answers the call from Arthur West and agrees to meet him. After hearing a taped conversation between J. J. Stanley and Ned Bain talking about the blackmail offer, she hires Perry Mason. Ned Bain decides to pay and meets with J. J. Stanley. The next morning J. J. Stanley is found dead in Arthur West's hotel room. Harriet Bain is accused of the murder when her fingerprints are found on the murder weapon.

Janet Norris is charged with poisoning her doctor husband just before he flew to his death in his private plane. Further investigation reveals that Dr. Norris did not die in the plane crash and that he is in Mexico with his nurse mistress. The man killed in the plane was actually one Dave Kirby. This means that Janet still has to stand trial for murder.

Della and Perry's dinner at a fancy French restaurant is interrupted by a phone call and an envelope containing $500.00 from a mysterious woman named Marian Fargo. She wants him to make an exchange for her: the money for some documents regarding her fugitive brother. Unbeknownst to Marion, her own husband is in on the blackmail scheme which is being masterminded by one Samuel Carlin. Marion's husband and Carlin both turn up dead but Marion, who has fled on a bus, has an eyewitness, Diana Maynard, who can provide her with an alibi for the murders. Unfortunately for all concerned, Ms. Maynard has only one good eye and may not be telling the truth about who she is.

Doris Hocksley is shown a personal newspaper ad in a Los Angeles newspaper for locating the daughter of Adam Hocksley and providing proof of same. A friend, John Lowell, suggests she pursue the idea to prove she is the rightful heir to the Adam Hocksley estate.

Perry receives a telegram from Frank Lawton, an old friend of his, asking for his help as Frank thinks he’s about to be arrested.

Stefan Riker has come from Germany seeking the woman posing as Lisa Bannister—who is visibly shaken by his presence. Attempting to help her stepmother, Doris Bannister pretends to be romantically interested in Stefan Riker.

Daniel Conway is involved in a vicious proxy war with Warner Griffith for control of an oil company. Conway's secretary, Rose Calvert, is spying for Griffith. When Rose is found dead, Conway fears he's being framed for murder and approaches Perry at a bar association dinner and asks for his aid.

When Albert Sanders is charged with the murder of dance hall girl, Kim Lane, Perry offers to defend him pro bono because he knows Sanders is down on his luck and still devastated over the accidental death of his wife and children eight years before.

Gossip columnist Mary K. Davis is found murdered and it seems there is no shortage of suspects.