When her brother is murdered, China Valdez (Jennifer Jones) swears revenge on the corrupt Cuban government he had been protesting. She joins the resistance led by Tony (John Garfield), an American with a plan that promises devastating results to their enemies. First they'll kill a government official, then plant a bomb at the funeral, which will wipe out the dead man's associates when it explodes. All they need to do is to dig an underground tunnel from China's house to the cemetery next door.