One day, Amane notices a girl, Mahiru, soaking in the rain. He gives her his umbrella but becomes sick. After she nurses him back to health, the pair become close and perform favors for one another.
Mahiru sprains her foot saving a cat. Amane cares for her injury and carries her home. Grateful, Mahiru brings Amane meals. Her cooking impresses him, so they start sharing daily dinners, growing close.
Amane's mother Shihoko unexpectedly visited and found Mahiru hiding in his room. Assuming Mahiru was Amane's girlfriend, she treated her warmly. Seeing Mahiru's happiness when addressed by her first name, Amane also started using it.
On Christmas, Itsuki and Chitose visit Amane's house and meet his neighbor Mahiru, who is revealed to be an angel. Amane cares for sick Mahiru the next day.
Mahiru falls asleep in Amane's arms before he can tell her. The next morning Mahiru is embarrassed. Amane's parents visit him on New Year's Day and they all visit a shrine. Mahiru learns that Amane lives alone due to a past incident.
Amane got hot chocolate from Mahiru on Valentine's. She was shy. Mahiru went home before confessing feelings. Amane found chocolates and card from Mahiru, knowing Amane's sweet tooth. For White Day, Amane prepared a gift in return.
Amane sheltered runaway Itsuki. Chitose stayed at Mahiru's after hearing this. Later, Amane saw a haggard Mahiru talking to her mother Sayo. He invited her in and she opened up about her past as he held her hands.
The new term places next-door neighbors Amane and Mahiru in the same class. Their home life mimics marriage with Amane's meal orders and gift-giving. But Amane ignores Mahiru at school.
Amane and Mahiru go on a secret date during golden week. They hold hands and enjoy their time together until they encounter their friend Yuta. The next day, Amane feels pressure when Itsuki and Yuta ask about his relationship with Mahiru.
Because of a middle school event, Amane moves out solo. Mahiru comforts his sorrow and insists he lean on her. Mahiru later stuns Amane by confessing to classmates she dated over the holiday. She proclaims the boy is significant to her.
Mahiru had promised to grant Amane's wish if he placed in the top 10 on an exam. Seeing his childlike excitement, she smiled. They fell asleep. Amane awoke and took the sleepy Mahiru home but felt awkward entering her house.
