DI Ken Jackson's personal and professional worlds collide when a dark secret from his past comes to light. His colleague, DI Archie Bond, turns up at a police benefit boxing match with a young woman called Crystal and Ken is clearly stunned by her presence. He obviously knows the escort girl - but how?

Sgt Keith Lardner is concerned when Ken seemingly becomes obsessed with Crystal and asks Dangerfield to have a word with him. However, Ken is giving nothing away and Dangerfield is left thinking that the girl could be connected with the detective's shady past in the Vice Squad.

Then matters come to a head when a case of TB is uncovered at the surgery, but sufferer Gerald Norland seems reluctant to prepare a list of people he may have infected by close contact. Joanna Stevens then goes to treat Crystal's baby Emma and realises that the escort has TB also. As the TB is fairly isolated, she puts two and two together and realises that her patient was the one who infected Gerald Norland.