Akatsuki wakes in the school gymnasium with no memory of the previous day. Himeragi is beside him on a futon, dressed in vintage bloomers and a PE uniform, equally confused about how they got there. A bloody baseball bat lies nearby, and a mysterious purple undergarment has somehow ended up in his pocket. Neither can explain the gap in their memories or the bizarre circumstances surrounding them. As strange clues pile up, multiple factions mobilize to investigate what actually happened. A ship sits abandoned nearby, its secrets waiting to be uncovered. The stakes feel higher than a simple forgotten night, with various interested parties converging on the mystery from different angles. Akatsuki and Himeragi must piece together fragmented memories and cryptic evidence to understand what transpired and why so many powerful forces care about the answers. This OVA leans hard into supernatural comedy while maintaining the action-driven energy the series is known for. Expect absurdity mixed with genuine mystery, humor that doesn't take itself seriously, and the peculiar chemistry between its core cast under increasingly ridiculous circumstances.