The Comp is a popular portable game system that also functions as a smartphone. But it suddenly becomes a portal for demons to travel to the human world! Kazuya receives three Comps, from his master programmer cousin Naoya, for himself and his two friends Atsuro and Yuzu. In order to survive the demon invasion, the trio have to use the Comps to summon and subdue the demon that appears in order to fight back against the waves of demons that are about to swarm Japan!