March, 1918. British newspapers carry the dreadful news that the German Spring Offensive has begun, with thousands of British lives lost. Detective Sargeant Joe Keedy is awaiting release from hospital in London and is anxious to resume the fight against crime on the Home Front.

Late one night, a bank is raided by a gang and the villains escape by car with a sizeable haul. Detective Inspector Harvey Marmion is put in charge of the case, but without Keedy at his side he faces an uphill battle to solve this perplexing case.