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!
Erika and Sosuke finally meet again! The two hop into Sosuke’s blue convertible and zoom off to Enoshima for a date. Meanwhile, Nagi heads to the boxing gym with Hiro. But with the pressure of Ai-chan moving in with him, Nagi finds himself in a delicate situation as a fateful Christmas rolls around… What will happen on that silent night?!