Canadian World War II veteran John Graham (Robert Preston) works in London as a code breaker. Tragedy strikes when his pregnant wife, Carol (Elizabeth Sellars), is accidentally run over by two crooks who are speeding away from the scene of a murder. Haunted, grieving and thirsting for revenge, Graham sets out to find the two fugitive murderers. When he does, he intends to kill them, the same way they killed Carol. But will that assuage his grief?