Shingo Umoregi is a boy who is so obsessed with demons that he has earned himself the titled of "Akuma-kun" (Demon Boy). He has tried many times to summon the superstar of the demon world, Mephisto with many failed attempts. However, when a mysterious demon kid shows up in the human realm, he befriends Akuma-kun. Will this kid be able to assist Akuma-kun with summoning Mephisto?