Scotland Yard detectives Jack Holbourne and Harry Morgan are assigned to investigate and discover that all of the women had recently appeared in the pornographic magazine Playbirds.

Four suspects are identified: the magazine's publisher, Harry Dougan; photographer Terry Day; a street preacher called Hern; and anti-pornography campaigner George Ransome MP.

Lena Cunningham, Playbirds' next star model, is given round-the-clock police protection, but the killer takes advantage of a brief security lapse to enter her flat and murder her in the living room, thus claiming his fourth victim.

Following "auditions" at the Yard, in which female officers are made to perform striptease, Holbourne and Morgan recruit Sergeant Lucy Sheridan, who takes a job at a massage parlour to set up her introduction to Dougan.

The title sequence shows Millington walking through Soho when it was at the height of its domination by the sex industry, giving a visual record of the district's history.