For months a killer known only as "the Sinful Strangler" has stalked the streets, murdering ladies of the night like a modern Jack the Ripper. Lieutenant Lou Crawford decides on a desperate plan: he seeks out a mysterious woman who sells to him a formula that will change him into a woman for one 24 hours. Disguised as the beautiful Lulu, he goes undercover as a prostitute. But will Lou find the Strangler before he kills again? And how far is he willing to go to maintain his cover?