1 - Death Runs Wild

Story tells of a demented woman out to kill private eye Anthony George. The instrument of death, as it turned out, was, a wild stallion she stocked on her ranch. Her motive was revenge. On a previous case, the private eye had brought her lover to justice and the gas chamber.

2 - Interrupted Honeymoon

3 - The Cyanide Touch

4 - Lady on the Brink

Checkmate comes to the aid of a woman with a traumatic past when it becomes evident that someone is trying to make it appear she's mentally unstable. discrediting her eye-witness testimony at a murder trial.

5 - Face in the Window

6 - Runaway

A girl shows up at Corey's apartment, claiming that she is running from someone who is trying to kill her. However, the detectives all find that nothing she has said checks out, including her numerous aliases, and that she's actually an heiress running from a controlling grandmother. But it does appear that the part about someone trying to kill her may be the truth.

7 - Target: Tycoon

8 - The Deadly Shadow

9 - The Dark Divide

Barbara Rush plays a dual role in The dark divide. Why should Margaret Russell's life be threatened? Her aunt keeps getting phone calls from a woman named Nikki Garnett, threatening Margaret. What motive could the woman have?

10 - Moment of Truth

11 - The Mask of Vengeance

12 - The Murder Game

Attorney Emory Olivant invites Corey, Sills and Dr. Hyatt to a party. Once all the guests have arrived, Olivant announces that they are going to play a game—a murder game in which he will be the killer.

13 - The Princess in the Tower

14 - The Terror from the East

15 - The Human Touch

Arguably the finest episode of the series, featuring guest star Peter Lorre as an ex-con criminal mastermind determined to wreak revenge on master criminologist Sebastian Cabot. An intricate series of cat and mouse moves between the two geniuses culminates in a surprise and ultimately poignant ending, befitting the episode title. This episode stresses the close friendships between the three detectives of CHECKMATE INCORPORATED as it contrasts with that of the brilliant, but soulless Lorre. Directing, writing and acting are all exemplary.

16 - Hour of Execution

17 - Don't Believe a Word She Says

18 - Laugh Till I Die

19 - Between Two Guns

20 - A Matter of Conscience

21 - Melody for Murder

22 - Phantom Lover

23 - The Gift

Lola Tuscany, a temperamental lady soprano, is having premonitions of her death. After her concert she is almost poisoned and Checkmate Inc. is hired to keep her safe. Don Corey is skeptical, believing it is a publicity stunt, until he is nearly killed when a bomb explodes in the car he and Lola are driving in.

24 - One for the Book

25 - The Paper Killer

26 - Jungle Castle

After two attempts on his life, big game hunter Lee Tabor brings Dr. Hyatt and Carl to his home in the Malayan jungle. He asks for their help in finding out which of his three house guests is trying to kill him.

27 - The Deadly Silence

28 - Goodbye Griff

""Ex-convict Griff Nolan is jealous because his wife Libby earns more as a magazine editor than he does as a mechanic. More domestic strife develops when Griff becomes jealous of Libby's boss Lewis Bates --- and buys a gun."" -- TV Guide

30 - Voyage Into Fear

31 - Tight As a Drum

32 - Death by Design

33 - The Thrill Seeker

34 - Hot Wind in a Cold Town

35 - A Slight Touch of Venom

36 - State of Shock