A Couple Of Cuckoos Vol. 1 (Light Novel)

Nagi Umino is a second-year high school student who was mistakenly switched at birth and now attends a prestigious high school. One day, while going to meet his biological family for the first time, he runs into Erika Amano, a popular internet celebrity on her way to meet her future fiancé who makes Nagi act as her fake boyfriend. But little do they know the shocking truth that awaits them: that they were both switched at birth and that Erika is to become Nagi’s wife! The curtain rises on a romantic comedy that begins with being switched at birth!
Notice: This book is written in Japanese.