The Kobayashi twins, Megumu and Mitsuru, were named after historical figures, but only Megumu has grown up with a taste for history. So when Mitsuru is in danger of losing his weekends to extra history classes, he convinces his sister to swap clothes with him and ace his tests! After all, how hard can it be for them to play each other?

Megumu has once again switched places with her brother, just in time to meet Akechi's newest student--the angry guy she encountered in the park! Chiharu Uesugi knows something about Aoi's past and seems determined to take him down. Megumu wants to protect her boyfriend, but will she be able to foil whatever nefarious plan Uesugi has cooked up when he blackmails her into a date?!