Due to frequent misadventures with the supernatural and her hectic school life, Nene Yashiro can barely catch a break until Kamome Academy's annual sleepover event comes around. Nene is excited to blow off some steam with her best friend Aoi Akane and the rest of her class at the get-together. Unbeknownst to her, the sleepover falls on the same date as Urabon, when the line between the dead and the living gets distorted, allowing wicked spirits to come out to the surface.
When an evil ghost is about to attack her, Nene is rescued by a mysterious figure: Shinigami, the Sixth Wonder that can trap souls using his flute. In that moment, Shinigami takes notice of Aoi and abducts her to use her as a sacrifice that will close the barrier for good. Joined by Hanako-kun and Akane Aoi, Nene must embark on a journey into the deepest confines of the world of the dead to save her best friend before it is too late.