Frank and Joe are invited to join a charter flight which passes over the Bermuda Triangle.

Nancy goes under cover to keep a light-fingered tennis star out of trouble.

Nancy is determined to restore the honor of a dear old gentleman who claims to be Santa Claus when he is accused of burglary.

Nancy is held for psychiatric observation when she tells the police an unbelievable story.

After Joe Hardy's fiancée is killed by a hit-and-run driver, the FBI won't let the police arrest the man until their own case against him is finished. Joe takes the law into his own hands and goes undercover as a rich gambler with underworld connections.

Joe Hardy is still haunted by memories of his dead fiancee, but has to focus his mind on the case when Jocco's girlfriend overhears him talking to the police on the phone. Meanwhile, Frank Hardy tries to help Joe by going undercover too, but Jocco finds out and traps Frank in a shark-infested area.