A year ago, acting on faulty intelligence, officer Paul Tallis shot an innocent woman suspected of terrorism in a Birmingham shopping center. With his career over and his conscience in tatters, Tallis left the elite firearms unit utterly disillusioned.

Now a shadowy figure working for MI5 approaches Tallis. The offer is simple—unearth four dangerous illegal immigrants accidentally released from prison, and hand them over to the authorities. At first the plan runs like clockwork. But then, with the authorities demanding their last fugitive, he makes an ugly discovery—Tallis suspects he's being set up…and that the last exile is innocent.