There have been many reports of supernatural occurrences at Kamome Academy, and the topic of the "Seven Enigmas" is commonly discussed. One of the most popular tales is about Hanako-san, a ghostly girl who is said to haunt the third-floor bathroom of the old school building. According to whispers, those who summon her can have their wishes granted. Nene Yashiro, a first-year student, calls upon Hanako-san in hopes of finding love, but is surprised to find that the apparition is actually a boy. Despite Hanako-kun's reassurances that he doesn't have any magical powers to offer, Nene tries everything she can to get his attention. In her desperate attempts to win him over, she consumes a fish scale that turns her into an aquatic creature, putting her in danger. Hanako-kun comes to her rescue and their fates become intertwined, with Nene now serving as his assistant. As she delves deeper into the world of the supernatural, Nene discovers that the Seven Enigmas are more than just rumors.