16-year-old super-studier Nagi Umino, second-year student at the Megurogawa Academy high school, was switched at birth. On his way to a dinner to meet his birth parents, he accidentally meets the brash, outspoken, Erika Amano, who is determined to make Nagi her fake boyfriend as she never wants to actually marry. But once Nagi makes it to dinner, he finds his parents have decided to resolve the hospital switch by conveniently having him marry the daughter his birth parents raised...who turns out to be none other than Erika herself! "Why don't we date each other...?" Nagi is lost for words when faced with Hiro's abrupt confession of her feelings, but after some soul-searching he manages to find an answer! With fall midterms looming on the horizon, Nagi and Hiro are once again competing to be at the top of their class. Meanwhile, Erika is planning something, Sachi is at Meguro Shrine, and Ai-chan is...the new Umino live-in maid...? The sparks from these teens' feelings are about to bring them to a juncture of destiny!