The Vice Squad investigate a series of murders of street prostitutes. Chappel gets involved with a young prostitute and is convinced that an arrogant city slicker who has befriended her is behind the murders.

DI Chappel targets a former porn baron who is still involved in prostitution. PC Morgan goes under cover as a party prostitute but takes the role too far.

DI Chappel goes under cover as a lodger to investigate a suspected porn merchant, but PC Hutchins discovers the house is the base for a paedophile ring.