What might be a violation of instructions for one is a normal working day for Detective James Knight. While hunting robbers, the elderly cop broke the law and ended up in jail. While his friend and partner Fitzgerald is re-learning to walk after being wounded, Knight plays cards with other inmates and attends Christian meetings of the preacher Father Conlan. On Christmas Eve, James is released, but New York City is attacked by a band of anarchist bombers dressed as Santa Clauses. The policeman begins to search for the gang, not suspecting that their leader is well known to him.