When Starsky offers for himself and Hutch to check on a waitress's missing friend, they find the man dead, leading them to stumble across a plot to rob an armoured car by a gang that are holding the driver's pregnant wife hostage, forcing the driver to go along with the plan...

Bent on seeking revenge against Hutch a mad chemist mistakenly injects Starsky with a lethal poison that will kill him in 24 hours unless he finds the antidote in time. Things get worse when Starsky kills the only prime suspect who can identify the poison.