Young girls arriving from the North at London's Kings Cross Station are being forced into underage prostitution rings from which they cannot escape. Main suspect John Rutherford is believed to be based in Canley, so Sun Hill officers team up with British Transport Police to track him down. PC Gary Best goes undercover at the station, watched by a police surveillance teams. He rescues a young girl, Lorna, from a mugger and the two get on well. The pair are approached by Rutherford, who suggests they stay at a squat he knows. Gary is suspiscious, but doesn't want to leave Lorna in Rutherford's clutches. However, when the support team lose sight of him, Gary is in way over his head. At the squat, he is drugged and wakes up with no memory of the previous night when PCs Des Taviner and Reg Hollis raid the house. As Gary struggles to come to terms with the fact that he may have been raped, PC Honey Harman discovers Lorna is not the innocent girl she appears to be. Supt. Adam Okaro comes unde