Private eye Bill Crane is back, in his fifth and final case, working and drinking as usual with his old sidekick, Doc Williams, and a new member of the gang, Ann Fortune, who is posing as his girlfriend - and disapproves of his carousing.

The trio has been sent to a Chicago suburb to investigate a murder and death threats made to the family of an industrial magnate. Alternately impeded and abetted by the many attractive women of the family, Crane cracks the case in his own inimitable way, following a trail of clues including the perfume of gardenias, the lipstick marks on the dead man's face and the crimson cat.