At her local gym PC Cathy Bradford is concerned that Marti Hunt is being worked too hard by her father Barry Hunt who is also the owner. As she leaves, Bradford agrees to keep an eye out for a petty thief who has been targeting the gym. Back at the station PC Dave Quinnan mentions to PC Tony Stamp that he is thinking of asking out Liz Terry from the Day Centre. Stamp is sceptical and encourages a wary Polly Page to check Liz's history on the police computer. Page is left with a dilemma when the results reveal that Liz used to be a prostitute. Meanwhile a reluctant PC Jim Carver has joined Bradford's gym. He is immediately suspicious that bodybuilder Jay Cutler could be the thief especially when he later sees Cutler selling steroids in the changing room. However, closer inspection of another gym member Andy Little leads to the case taking an unexpected twist.