Busses Roar

A group of Japanese spies plan to blow up a San Francisco-bound bus in the hopes that the flames of the explosion will act as a guide to a lurking enemy submarine to shell one of the valuable CAlifornia oil fields. Among the many passengers is Reba Richards (Julie Bishop)who inadvertently carries the bomb in her suitcase. She discovers it and, with the aid of a United States Marine, Sergeant Ryan (Richard Travis), works to squelch the bomb and trap the culprits. - IMDb