Following a court appearance for drunk driving, Leo is required to perform unpaid work as a punishment, assisting AJ, a community worker on a run-down,largely black-occupied housing estate in South London. AJ is hoping to divert boys away from crime by encouraging them to do sports, and, though initially dismissive of Leo as a white intruder, comes to respect him after he has saved the life of Errol, a former gang member now anxious to keep his little brother Levi out of trouble. Errol has been stabbed in the leg by members of a gang from a rival estate and Leo stops him from bleeding to death. Earlier in the week a young girl called Shana Block was stabbed to death at a funfair and her murder recorded on a mobile phone. As Shana lived on the estate police sergeant Wallace involves Leo as a go-between with the suspicious residents. Also on the scene are Harry and Nikki, the latter dating Ryan, a young Scottish paramedic she met when called to the scene of Shana's death. Before any arrests can be made, Richard Ojana, a member of a rival gang, is shot in broad daylight and nobody is willing to come forward as a witness. Believing he knows who the killers are, Errol goes off into the night, but the next day his corpse, tarred and feathered, is dumped on A.J.'s recreation ground.

The body of young Colin Connor is found in an attic at a former hospital now marked for residential development. He had been stealing metal but was locked in the attic by his accomplice who then fled. The culprit seems to be Derren Blackburn whose father lies for him when D.I. Cherry visits with Jack. At the same time, Leo is asked by distraught father Tom Hancock to conduct a post mortem on his son Peter, who, Tom is convinced, died because of electrical towers outside his window. Leo is surprised to find that Peter and Colin had an identical kind of kidney dysfunction. James Embleton, a government minister who begins dating Nikki, is in charge of the hospital conversion, and is visited by the sinister David Loader, who warns him of Leo's investigation into Colin's death. Leo and Jack look for proof of toxicity at a farm near the hospital, but are evicted by the army. Leo contacts George Ryder, who owned the farm, and they agree to meet at the hospital as George has an important revelation, but tragedy intervenes.