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 examination of the latest body from the housing estate proves it to be that of Errol Harris who was asphyxiated while being tarred and feathered. The policeman in charge of the case, DS Nick Wallace, is exasperated at the lack of physical evidence the pathologists are able to provide him as without concrete proof of who is involved in the killings, he knows they will never get a conviction. Leo Dalton thinks that the key to getting information is Errol's younger brother Levi who is actively being recruited to join the gang. Tragedy ensues however after the police question the boy. Finally at their wit's end, Leo comes up with a piece of evidence that has been available from the very beginning of the case.

Nikki is humiliated in court when a barrister accuses her of making a serious error in the case of a policeman who may or may not have been murdered.

When Thomas sides against her findings on a controversial case, Nikki suspects foul play and takes steps to prove her theory.