Christmas Eve night. Seto Kazuki was walking through the illuminated streets with his best friend Teratani. Today, they're at a Christmas party with Iori Reedzuki and Morisaki.

Kazuki is suddenly confronted by his childhood friend Itsuki, whom he has not seen in four years, in his underwear. However, Kazuki's feelings for Iori grow, and he tells her that his relationship with Itsuki is "just a childhood friend".

Kazuki hugged a sobbing Itsuki. Since then, he is confused by his wavering feelings.

Invited by Teratani to a study camp by the sea, Kazuki meets Izumi Isozaki, a girl standing alone on a rocky beach!　He is shocked and depressed by her disdainful gaze.

The day of the Christmas party finally arrives!　Kazuki confesses his feelings to Iori, but the drunken Iori doesn't understand his true intentions... Then, the after-party. Thanks to Teratani's consideration, Kazuki and Iori are left alone together. Kazuki is surprised to hear from Iori that he has been accepted into the theatre company. Meanwhile, Iori has to attend an audition at short notice at the request of the office..!

After graduating from high school, Kazuki becomes a ronin and Iori joins Isai Productions to pursue a career in theatre. Kazuki and Iori start dating after he confesses his love to her on Christmas Day, but a commercial featuring Iori sparks his popularity and keeps him busy. They find it difficult to find time for each other, and their lives continue to diverge.