London, February 1918. A burglary in Limehouse in the small hours of the morning has escalated into a sinister siege between a band of thieves and the authorities, and a police constable lies dead. Detective Inspector Harvey Marmion and Detective Sergeant Joe Keedy hasten to the scene where attempts at talking the men into surrendering have been met with stony silence. When the door is eventually battered down, Keedy bravely leads the way in. Then a gunshot is heard: Keedy has been hit. While his partner is rushed to hospital, Marmion is on the trail of the burglars. Keedy, however, remains in the sights of the murderous thieves and the clock is ticking as Marmion delves into the secrets that lie behind this fatal incident...