Perry drives to the scene of a shooting and finds the police recovering the body of Harry Merrill from a car that went over the side of a mountain. MerriIl has a bullet in his body and a pillowcase over his head. Meanwhile, Perry's client, Evelyn Bagby, claims she was chased by a hooded man in a car near the same cliff that day. She fired two shots at the man's car to scare him off, and now the police want her for murder.
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. 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.
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 fiancé. Later, 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. Later, Norton is found dead and Rodney Gleason, Fran's fiancé, is identified as the perpetrator.
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. When Sam Lynk is found dead in his home, Mildred Kimber is accused of the crime.
Carla Adrian is having trouble fending off amorous neighbor Mark Cushing. When another neighbor hears a shot and a woman's scream, then witnesses Carla's Mother, Belle Adrian, in Mark Cushing's cabin—it's not long before the police discover Cushing’s body and arrest Mrs. Belle Adrian.
In a few day’s time, Fay Allison is getting married to Dane Grover. Her roommate, Anita Bonsal, is having a clandestine affair with a married man, Carver Clement. Fay Allison is later accused of Clement’s murder when the police find her fingerprints on a glass in his apartment.
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.
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.
While Martha Bradford is waiting for her appointment at a beauty parlor, she meets Rita Bradford who apparently is also married to her husband, Joe Bradford. Joe is found dead on his boat the next morning and Martha Bradford is accused of his murder when her fingerprints are found on a candle located on the boat.
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 both 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.
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. Later, Nadine is accused of poisoning her uncle.
Claire Olger, a hitchhiker, is picked up by Michael Greeley. He loses control of the car and has an accident due to his being intoxicated. Eventually, 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.
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. When J. J. Stanley is found dead in Arthur West's hotel room, Harriet Bain, Ned Bain's daughter, is accused of the murder.
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. Later, Marion's husband and the man blackmailing her, Sam Carlin, both turn up dead.
When Robert Crane is charged with the murder of his sister's estranged husband, Perry needs the testimony of sister Helen Reed to clear him of the charge. Unfortunately for all concerned, Helen suffers from multiple personality disorder.
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.
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.
When wealthy Louise Gordon is poisoned to death her nurse is charged with the crime. Perry does some digging and discovers that the first wife of the victim's husband also died of poisoning. Is the husband really the culprit or could it be someone else?
Perry and Della are traveling on a cruise ship returning to Los Angeles from Vancouver. A fellow passenger, Carl Houser, who recently came into a bunch of money, and his wife and daughter end up meeting the two. Houser’s wife, Anna, enlists Perry’s help because she believes something is wrong with her husband and his story. Then her husband ends up overboard and she is suspected of murdering him.
Racketeer George Castle kills Las Vegas hotel owner Glenn Faulkner over a gambling debt and sets his sights on land inherited by Faulkner's daughter, Stephanie. When Castle turns up murdered as well, Stephanie finds herself the number one suspect.
Enid Griffin, the secretary of Stewart Brent, attempts to commit suicide after learning her boss has married. Arthur Binney attempts to blackmail Stewart Brent with facts about his new wife having been in jail for fraud. When Stewart Brent goes to meet Arthur Binney at a motel for the payoff, he is knocked unconscious. He awakens to find Arthur Binney dead in the next room and is put on trial for murder.
Attempting to miss hitting her stepfather's car, Patricia Faxon swerves as she enters her driveway and hits the hedges. After asking her stepfather, Bertrand Allred, to move his car, he finds Bob Fleetwood badly hurt next to the hedges. The next morning Bertrand Allred is found dead in his car.
Lorraine Stevens is fighting off the advances of the owner of the import-export company where she works, Philip Larkin. Later that evening she is asked to pick up something at the Alcorn Jewelers store. The owner is unaware of what she is to pick up and suggests she make a phonecall to find out. She calls Philip Larkin and while the phone rings we see Philip Larkin dead in his home.
While a woman is searching the office of the South African Diamond Company, George Baxter enters to meet Walter Lumis and Duane Jefferson. He notices things in disarray and questions the woman. She makes an escape, enters Perry Mason's office, and pretends to be a typist sent by a temp agency.
When Daniel Reed (Edgar Stehli) finds himself being blackmailed by an old business partner from his time in Alaska, Perry must first save him from the insane asylum and then the gas chamber.
