Mitsukai Dokuro is an angel that comes from the future and decides to live with Kusakabe Sakura. She looks quite young and plays the cute, innocent act quite well. However, every time something happens, she beats Sakura to death with Excaliborg, a special bat with thorns. But there is no need to worry, with the cast of a spell — Pipiru Piru Piru Pipiru Pi — he comes back to life.

As it turns out, there is a reason for these bloody heart-warming happenings: In the near future, Sakura will do something that will stop all girls from getting older when they reach age 13, and Dokuro was sent back in time to stop this from happening.