Ayumu Aikawa is dead - or was dead. This Ordinary High School Student has since been resurrected as a zombie by Necromancer-knight Eucliwood Hellscythe ("Eu"), who is now living at his house. Relaxing in the cemetery one night while searching for his killer, Ayumu witnesses a girl named Haruna fending off a giant monster with her magical chainsaw. She is a Masou Shoujo, having come from the magical world. As Haruna attempts to erase his memories, she ends up erasing her own powers (and outfit) by mistake. The Megalo won't cease attacking, though, and as Haruna is quick to discover, her powers have transferred to Ayumu instead. Ayumu is now a zombie and a magical girl, and hijinks ensue.