In the oppressive London summer heat, the unthinkable happens: a terror attack strikes the outskirts of the city.
Three airport-bound trains are brought to a standstill. Thousands are held hostage, trapped inside their carriages, with hours to spare until the explosives onboard detonate.
To save them, DC Jake Tanner must find the courage to stand up to one of the darkest evils he's ever encountered.
But first, he must play a part in their twisted games.
And the rules are simple: follow them, and no one gets hurt. Break them, and the consequences will be fatal.