When Futaba Yoshioka is nearing the conclusion of her first year of high school, she is taken aback when she unexpectedly runs with Kou Tanaka, the boy she first loved. Before she could let him know how she felt about him, he moved schools three years ago and left her in the lurch. Futaba realizes that he has gone through a lot of changes after they have reconnected and found out about his life. He has adopted a more sophisticated demeanor and has even changed his surname to Mabuchi. While gradually falling back in love with one another, they simultaneously piece together what took place during the period that they were separated.