Scientist Dr. Dobson and his wife Anne and son Greg move to Manila, Philippines in order for Dobson to continue his research work on developing an antidote for deadly germ warfare for the United States Army. Soon after the family's arrival, Greg explores his father's lab and comes upon several brightly colored small balls and, believing they are marbles, takes them, unaware that they hold the deadly germs Dobson is studying. While playing with the balls with his new friend Ramon, Greg becomes worried that he will be scolded for taking the objects and, along with his dog Candy, flees with Ramon across the city. Discovering the loss of the containers, Dobson realizes Greg has them and contacts the authorities and explains that the containers are constructed to disintegrate within twelve hours after contact with air, and release the deadly germs capable of destroying all life in a major city. The police and army join in the subsequent hunt for the boys, who are eventually found with Candy on the city docks, safe with the containers intact.