John Stitt and Max Cameron are two boys fanatical for the card game "Battle Day Zero." One day the combination of a wild storm and a mysterious booster pack suddenly means they can bring Hiro, one of the game's characters into their world. Excited but worried their secret will be discovered, the boys decide to take Hiro to school where he is mistaken for a Japanese exchange student. Despite this temporary solution the portal being open means that more people and monsters from Hiro's world can travel to Earth, wreaking havoc on the small town. The boys decide in order to get things back to normal they must send Hiro back but not before their school dance is overrun with Battle Day Zero characters.