Japanese spies plan to detonate a bus en route to San Francisco, using the resulting flames to guide a nearby enemy submarine to attack a California oil field. Unbeknownst to the passengers, a bomb is hidden in one of their suitcases, carried by Reba Richards. With the help of US Marine Sergeant Ryan, Reba works to disable the bomb and apprehend the perpetrators.
Busses Roar
A mysterious individual attempts to detonate an explosive device on a public transportation vehicle.
