Barbara Ingalls is accused of murder when her husband's mistress is found murdered. MacKenzie is asked to investigate the crime, but he discovers his life is also in danger because someone doesn't want him to arrive at a different conclusion.

A conman is trying to profit from the rumor of a volcano eruption. One of his marks hires Tracy to try and verify the rumor.

A manuscript said to have been written by Robert Louis Stevenson is stolen from a boat arriving in Honolulu. A man with a college tie to Tom enlists his help to track down the document.

Although Jean Morgan was found not guilty of her husband's murder, the public apparently is still not convinced. Jean hires Tracy to find solid proof of her innocence, while her stepson, Tony Morgan, hires Tom to find conclusive proof of her guilt.

Tom listens in on Kim's taxi radio and gets an alarming earful. Kim and his passanger, a girl named Joan Carmichael, are being forced at gunpoint to take a ride. Tom uncovers a murder while attempting to locate Kim and his passenger.

Greg and private investigator Tracy Steele investigate the attempted murder of an oil executive who was about to close a merger with a rival oil company, which is controlled by a woman.

MacKenzie (Grant Williams)runs to help when a car comes tearing down the street, barely misses him, and crashes to a stop. But he's too late. The man behind the wheel is dead - from a shotgun blast.