Umino Nagi was swapped with another child at birth. He's going to meet his real parents today, but on his way to school, he meets a girl who is threatening to die to get out of her engagement.
Nagi and Erica became engaged. However, Nagi realizes that the world she lives in is different. Erica, on the other hand, seems nervous. Is it a favor for Nagi or ...!?
Nagi and Erica have begun living together. Nagi is pleased to be able to concentrate on studying for the test, but life with Erica continues to happen. Can Nagi really get first place in the grade? Whereabouts of the game with Hiro...!?
Nagi, who took the first place in the test, is asked by Hiro why he is aiming for first place and confesses his feelings. Hiro replies that she likes smarter people than he does, but - soon she says a shocking word.
Nagi decided to study in the library in the morning with Hiro. He even wants to know common hobbies and continue his morning activities. It's a soaring calm, but a ridiculous situation that shakes the relationship between the two comes.
Erika participates in morning activities with Nagi and Hiro attempting to advance the relationship between them. Although, Hiro begins to say that she wants to visit Erika's home to get to know her better.
Nagi took the plunge and invited Hiro to the same group during a school event trip. At that time, she reconfirms the conditions for accepting the confession, and an unexpected word is returned. However, there is a problem with grouping.
Hiro Segawa invites Nagi on an unexpected morning "date" to collect temple stamps. Nagi dresses up, only to discover they're heading to an amusement park-Hiro wanted to use the affectionate "couple's discount" and challenge his endurance.
It is Mothers Day, and Sachi gets Nagi to accompany her to the mall to choose a gift for their mom. Despite his initial skepticism, they bond while shopping and notice Sachi being approached by admirers-a sign of her growing maturity
During a blackout, Nagi accidentally pins Sachi, mistaking her for Erika, creating tension between them. Sachi becomes distant, confused by her feelings. Erika urges Nagi to apologize, and he does so sincerely. Their bond begins to heal.
Nagi declines Erika's invite to go shopping, saying he has to study He instead invites Hiro to join a study session at the library Since talking is banned, they communicate via handwritten notes creating a surprisingly intimate atmosphere.
Nagi drops to 13th place in exams, shaken by his tangled feelings for Erika, Hiro, and Sachi. Hiro distances herself, upset. Erika tries to cheer him up but argues with him.
