07:45 a.m. A monk lies dead in Snowdonia, a knife protruding from his throat. A young family is being held at gunpoint in a house in Wimbledon. The mission has begun.

08:56 a.m. A London Underground train is stationary in a tunnel, four hundred passengers trapped inside. All efforts to communicate with it have been met with silence.

09:15 a.m. DCI Ed Mallory has just started his day. The Met's top hostage negotiator—despite having been blinded thirteen years earlier—Mallory is about to discover that, today, an underground train is not the only thing on the line.