Mannix is left holding the bag when he's hired by Pete Neal, a man he knows, to protect a man with $25,000 that they both claim isn't stolen. Neal is killed, and Neal's body, the man, and the money disappear.

Mannix works with a police detective to find the reasons behind the death of Peter Martin. When Mannix accuses Carlos Valera, the private eye takes on more trouble than he bargained for. After Valera's arrest, Mannix begins to have doubts about his guilt and begins digging further into the case despite hostility from Valera's neighbors as well as Martin's sister.

Mannix launches a double-edged search for Brad Turner and Jimmy Whitewing, two friends of Peggy's, who are wrongly accused of murder, and for the real killer who can only be linked to the crime by a dancer. Brad and Jimmy seek refuge in Peggy's apartment, but flee when Mannix offers to help them under the condition they tell their story to the police.