Henry Graves has dedicated his life to the prison service, but he is unprepared for the challenge his new and secret assignment brings. Tasked with managing a government facility hidden deep in the countryside, Henry finds himself tested as never before: by the confused and frightened prisoners, by the sinister Dr Silk and, above all, by his conscience.

Tom Clarke, a precocious but naive journalist, has his own problems meanwhile. His career - and his life - is turned upside down by the arrival of Julia Priestley, who seeks his help in finding her estranged husband, Arthur, an innocent dentist who has been arrested under severe new anti-terrorism legislation. The authorities admit they have taken him but will not say where he is being held - or why.

Discovering a trail that implicates those at the very top of government, Tom and Julia begin a quest to find Arthur, and the truth about his incarceration. But some people will stop at nothing to keep the facility’s secret hidden, and soon the couple find themselves fighting for their lives …