During their first night sharing a room, Yuzu had her first kiss stolen by her step sister. Since then she can't get Mei off her mind, while Mei herself goes on as if nothing happened. Meanwhile, Mei's Grandfather, the chairman of Aihara Academy, takes Mei back to his mansion. Unable to forget the sad expression on Mei's face when they kissed, Yuzu heads to the mansion to confirm Mei's true feelings, but...?!

After confronting Mei with her feelings and kissing her in the chairman's office Yuzu isn't able to face Mei and agonizes over it. Meanwhile, the student council vice president who's also Mei's childhood friend, Momokino Himeko, becomes suspicious of what happened in the chairman's office and meets with Yuzu on their day off to discuss it. There she tells Yuzu, "She's incredibly sad. As sad as she was when the current chairman, her father, left her," leaving her in shock. Yuzu's weakly walking to the station home when Mei appears before her...

Mei's father, Aihara Shou suddenly returns home. While Yuzu is surprised to meet him for the first time, she explains to Shou how hard Mei's been working for the academy. However, Mei screams at her to stop when Shou just silently averts his eyes with hesitation. Shou tells his daughter, "I'm not returning to the academy." Yuzu is unable to say anything as Mei runs away to their bedroom, and that night she tries speaking to Mei again.

With her dislike of Yuzu and Mei's relationship, Matsuri uses the secret photo she took at the shopping mall to blackmail Mei into fooling around with text-pal on Christmas. Meanwhile, Yuzu knows nothing of this and struggles to bake a cake for her first Christmas together with Mei. While her excitement builds, Mei comes home and breaks the news that she won't be able to join their Christmas Party due to student council work...

While Mei was able to accept her feelings on Christmas night, for some reason Yuzu couldn't respond sincerely. Ever since then the two have barely exchanged words and their relationship only grows more awkward... More time passes until the school field trip draws near. On the day of the trip Yuzu oversleeps and dashes to the station, but she's too late to catch the train. While she's feeling depressed she runs into a pretty young girl, Tachibana Sara, who also missed her train.

Yuzu manages to reunite with her class, and then at the hotel she tries to confess her feelings and talk about that Christmas night with Mei. However, Mei tells her to forget about that night... Tachibana Nina happens to witness their exchange, and knowing about how her twin sister feels as well as her relationship with Yuzu, Nina resolves to help fulfill her sister's destiny. The next day Sara and Nina beat Yuzu's class to Yasaka Shrine, waiting for their chance.

Yuzu promises Nina that she'll support Sara's love with her, but after learning that the girl of Sara's destiny is Mei, she can't help but feel shaken. Nina ignores all the attention she's drawing, desperately holding Yuzu back to keep her from going to Mei. During their conflict Yuzu gets a call from Sara on her smartphone, saying "There's something I need to give you." She quickly races to the overlook, but Mei isn't there, only Sara greeting her with a slightly sad smile as she returns the student ID Yuzu dropped earlier.