Nagi Umino, a 16-year-old super-student and second-year student at Meguro River Academy, was swapped at birth. On his trip to visit his biological parents, he meets the boisterous, outspoken Erika Amano, who is eager to make Nagi her false boyfriend because she never wants to marry. When Nagi arrives at supper, he discovers that his parents have chosen to address the hospital switch by having him marry the daughter his biological parents raised...who happens to be none other than Erika herself!