GBH, short for Grievous Bodily Harm, is an unnerving tale of paranoia and madness in the heart of the 1970s London criminal underworld. Two intertwining narratives - past and present - chronicle the man's tragic fall from power. In London, Fowler resides at the head of a lucrative criminal syndicate that specializes in the production and distribution of "blue films" - illegal pornography and some nasty stuff. Fowler is king, with a beautiful girl at his side and a swanky penthouse office atop a high-rise, but his entire world is in jeopardy.

Someone is undermining his empire from within, and Fowler becomes increasingly ruthless in his pursuit of the unknown traitor. As his paranoia envelops him, Fowler loses trust in just about everyone, including his closest friends and associates, and begins to rely on the opinions of an increasingly smaller set of advisors.

Juxtaposed with the terror and violence of Fowler's last days in London is the flash-forward narrative of his hideout bunker in a tiny English beach town, where Fowler skulks during the off-season among the locals, trying to put together the pieces of his fallen empire. Just as it seems possible for Fowler to reclaim his throne, another trigger threatens to cause his total, irreparable unraveling.