Nagi Umino, a sixteen-year-old model student, decides to see his biological parents after learning that he was switched at the hospital after his birth. Erika Amano and him run into each other by chance as he travels to a dinner reservation with them. She attempts to convince Nagi to act as though they are a couple so that her parents will abandon the notion of having her wed to an outsider using her demanding demeanor.
When Nagi shows up at the designated meeting spot, he learns that Erika's parents are actually his birth parents, which at first seems strange to him. And they decided to wed Erika and Nagi in order to atone for the mix-up at the hospital all those years ago.