A terrorist code-named Cerastes is on the loose, and an undercover anti-terrorist squad have planned a sting to capture him as he steps off a train at a London station. The operation, led by the buffoonish Acting Major Quentin Sexton, has drawn in two outsiders - Ez and Barry. Perfect strangers as the play begins, their time waiting for the trap to be sprung gives them the chance to get to know each other, and try to make sense of the chaos unfolding around them.