Following an anonymous tip-off, the team organise a raid on the flat of Connor Tierney (Ian Puleston-Davies), the man they suspect of being the supplier of uncut heroin which has resulted in four drug-related deaths. However, during the raid, Tierney claims that a twelve-year-old boy, Lee, who has been staying with him, has vanished. Tierney is taken in for interrogation, while the search for Lee gets underway. Lee's mother, Bernadette, appears to have little care for her son, even when he turns up dead on a piece of overgrown wasteground. Tierney claims that Bernadette was the one responsible for dealing heroin, and that he only ever supplied one of her desperate customers while she was away. Meanwhile, Hill pressures Pauli to take her relationship with Sullivan to the next step in order to secure him as an informant. Pauli, however, is less keen on the idea and suggests that the team drop their pursuit of Sullivan. Cally becomes worried when Carmen fails to sign for her bail, but discovers that she has made an unlikely new friend.