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's life has gone from weird to wonderful--she no longer has to cross-dress as her brother, and her true love, Aoi, has asked her out on a date! It's the beginning of a beautiful relationship, even if they have to stay two feet apart at all times or risk Aoi going into anaphylactic girl shock. Meanwhile, Mitsuru is back in his own clothes too, but he's making war, not love! Can he defeat the school bully and win the hand of his sweetheart, Shino?!