February 1918. Detective Inspector Harvey Marmion and Detective Sergeant Joe Keedy are pulled from their beds to attend a sinister siege involving three burglars where one policeman has already been shot dead. Attempts at talking the men in the house into surrender are met with stony silence so the police proceed to batter down the door and Keedy bravely leads the way. A gunshot is heard. Keedy is hit.

As Keedy is rushed to hospital, Marmion is on the trail of the men who fled the scene and startling revelations emerge. A cold-blooded killer is intent on finishing the job he started and has Keedy in his sights.