Nagi Umino and Erika Amano, a studious high school student and a social media star, had nothing that linked them together—until they found out they were swapped at birth. When the sudden news is revealed to both of their families, their parents quickly devise a proposition with neither Nagi's nor Erika's knowledge: in order to restore them both to their rightful families and ensure everyone's happiness, the two should get engaged. When informed of this, Nagi and Erika are quick to reject the absurd plan, refusing to go along with their parents' wishes. But, with neither party willing to back down, only time can tell where their relationship will go. 16-year-old super-studier Nagi Umino, second-year student at the Meguro River 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!