Kyutaro Horikita, the tall, dark and handsome cleaning expert of Kurokado High, is about to meet a sleeping maiden at the school: transfer student Fumi Nishioka! Fumi's going to learn how to rid the school of nasty spirits with Kyutaro's help, and her heart will surprisingly be "cleansed" too...!

In the old campus of their school, a mysterious room has a door that beckons Fumi, even though she shouldn't even be able to see it! Kyutaro goes in after her, but will he be able to save her before she gets devoured by otherworldly creatures?