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!
Reeling from Sachi’s shocking New Year’s confession, Nagi heads out for his first shrine visit of the year and runs into his ex-girlfriend Hiro. Meanwhile, Sachi has gotten serious about her high school entrance exam prep, despite taking breaks to eat ramen or hit the sauna. Can Nagi lead her to victory as her home tutor? And how will he respond to the feelings Sachi confessed?!