Leonie is one of twelve jurors. Chosen to decide the fate of a nurse accused of murdering his patients with lethal doses of adrenaline. But just as deliberations begin, an usher bursts in with news that will change everything. Britain is under chemical attack, and the courthouse is locked down.

Instructed not to leave for their own safety, the jurors quickly realise that the real threat lies inside the building. The accused has escaped his cell and is on the loose. He's playing twisted games with the group. And Leonie is his next target.

Because he knows something about her. A secret she's kept hidden from the others - about just how far she'll go to tip the scales of justice in her favour.