Chappel goes undercover in a prison to flush out the ringleaders of a prostitution racket thought to be pimping young women to inmates. PC Hutchins, posing as Chappel's girlfriend, is targeted by the group.

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.

The Vice Squad investigates an amusement arcade manager suspected of recruiting young runaways as rent boys.

PC Sparkes is in a tricky situation as the male teenager who has been befriended by the amusement arcade manager, takes a shine to him and makes his undercover role uncomfortable. When the Vice Squad perform a bust he is mistaken for a punter.