One day, Marisa Kirisame decides to break into the Scarlet Devil Mansion's library to "borrow" some of Patchouli Knowledge's books, as usual. However, this time she was caught off guard as she was surrounded an army of heavily-armed fairies and ant-like robots all under Patchouli's control.

One day, Marisa Kirisame decides to break into the Scarlet Devil Mansion's library to "borrow" some of Patchouli Knowledge's books, as usual. However, this time she was caught off guard as she was surrounded an army of heavily-armed fairies and ant-like robots all under Patchouli's control.