Horimiya -The Missing Pieces-

Hori Kyoko, a popular, beautiful, and bright girl. Miyamura Izumi, a gloomy, unassuming otaku. Two persons who are never supposed to cross paths discover each other's secrets one day. Although they are shocked by how different the other person is in reality, they promise to protect each other's secrets. And so, fate draws both closer and closer.

Living with Miyamura becomes Hori's new routine life. However, they still have a lot to discover about each other.

They are in the same class as they enter the third year of high school. Miyamura recalls his past and gets distraught: surrounded by warm people, does he really have a place in the group? With these complicated feelings, Miyamura continues his days. The relationship between Miyamura and Hori slowly changes as they care more and more about each other.

Despite some mishaps, Hori and others are spending more time with members of the Student Council. While everyone is spending their leisure time in the student council room, Remi speculates the relationship between Miyamura and Hori. Sakura slowly develops feelings towards Ishikawa. One day, a figure from Miyamura's past, his junior high classmate and close friend, Shindo Koichi, appears.

Miyamura confesses to Hori, who is lying on the bed due to a fever. He leaves after the confession. Hori feels conflicted as she doesn't know how to face Miyamura. And then, she hears rumors that Miyamura was holding another girl's arms on the street. Hori is shaken...

Hori and Miyamura recognize their own feelings and begin dating. One day, another student from school sees Miyamura exit Hori's house. The beautiful and popular Hori and the gloomy Miyamura? This couple piques everyone's interest. Due to the teasings, Miyamura does something...

Sakura, who has been secretly in love with Ishikawa, musters her courage and starts to take action.

The school's picture-perfect couple, Sengoku and Remi, start dating a while ago. Between Hori who wants Miyamura to become more "domineering", Yuki who receives a confession from Yanagi Akane, a handsome student, and Ishikawa who helps Yuki to reject Yanagi's advance by posing as her boyfriend... Love is going haywire.

Miyamura runs into Tanihara Makio, his junior high classmate. Since Tanihara and his friends used to bully Miyamura, he feels a bit awkward. On the other hand, noticing Miyamura's transformation, Tanihara finds it intriguing and starts pestering Miyamura...

Yuki and Ishikawa continue to pose as a couple. Sakura confronts Yuki about her relationship but Yuki cannot tell her the truth. Even though Yuki is sick of pretending, she decides nonetheless to continue acting. And suddenly, Sakura confesses to Ishikawa.

Yanagi is the latest member of the group of friends. More and more people surround Hori. Although Miyamura thinks Yanagi can be quite volatile, they still become closer. Iura then comes looking for Hori. Iura's sister, Motoko, is a junior high student sitting for an exam and Iura hopes Hori can tutor his sister.

It's December. Christmas is around the corner. Remi wants to invite Sengoku to hang out in her room while Miyamura is busy manning his family's pastry shop. Everyone is celebrating Christmas in a different way. Hori looks forward to the festivity but when she thinks about her graduation next year, she feels lost. What will become of her relationship with Miyamura...?

It's March now. Hori and others will graduate from Katagiri Senior High School soon. With the friends and memories they make all along, they step forward to the new future.