Haruka Nogizaka's Secret

Yūto is invited to come with the Nogizakas to a ski resort in the mountains. He thinks it is just for them but he quickly finds out the entire class is coming on this trip. While the group enjoys all the hot spring resort has to offer, Shiina sees the trip as an opportunity to express her feelings to Yūto—but in an attempt to hug him, she ends up groping Gento, who was covered in sheets. An enraged Akiho catches them in a compromising position and gets the wrong idea, causing Gento to pass on the group's shrine visitation the next day. The next evening, a blizzard arrives and Haruka goes missing on the top of the mountain. When Yūto, equipped with an insulated polar bear suit, finds her, they both fall down a ridge and become stuck in a cabin. As she is wet and freezing, Haruka takes off her clothes and joins Yūto in his bear suit in just her underwear. However, the two are quickly found not only because the bear suit has a tracking device, but also because the cabin turns out to be just behind the resort.

Haruka agrees to attend the audition for Yayoi and Nozomi. Yūto waits as Haruka gets ready for the audition, and is told by Yayoi not to interfere. While waiting, Yūto once again bumps into the girl he met before at the shrine, who turns out to be the idol Milan Himemiya. Milan decides she wants Yūto as her manager since her own manager is currently in a different prefecture. Yūto and Milan go around together to photo shoots, voice acting and other things. After his work as a manager, Yūto overhears Yayoi and Nozomi while poring over Haruka's photographs. It becomes clear to him that the talent agency actually wants Haruka to become an idol—something Milan had tipped him of earlier.

Yūto visits Mika's junior high school—an all-girls' school—upon her invitation. Mika introduces him to the rest of the girls in her class. He was surprised to know that Mika was a popular girl at school. She is a class president and a school idol, pretty much like her sister Haruka. After their meeting, Yūto decides to go and see Mika's stage play. After the stage play, both Yūto and Mika are accidentally locked up in the stage room. Luckily in the end, Mika's maids find them.

It is New Years Day and everyone has gone to visit the local shrine together. Although Haruka and Yūto were hoping to spend some time together, it is not long before Haruka's admirers, who are hostile to Yūto, whisk her away. Later, after both Haruka and Yūto receive encouraging fortunes (courtesy of Mika, Hazuki and Nanami—working as shrine miko), Haruka manages to get rid of those admirers. Haruka and Yūto bump into a mysterious girl, who is running away from someone. Later, Haruka takes Yūto to the cape where her parents shared their first kiss, so they can watch the sunrise together.

The Nogizaka family visits Yuuto's house for a Christmas party. However, the party is cut short when Yuuto faints, having worked himself to exhaustion to buy Haruka a Christmas present. When Yūto regains consciousness, Haruka declares that she will stay by his side in order to nurse him back to health, under the guidance of a very questionable guidebook prepared by Mika. To preserve the Christmas spirit in spite of Yūto's poor health, Haruka decorates his yard with Christmas lights, and presents him with a Christmas present. He in turn presents her with his present: a ring called "Clair de lune" which, at Haruka's request, he places on her ring finger. The two thus share another precious memory together.

Yūto and Haruka begin making a dōjinshi together, though Haruka's skill in drawing is still lacking. Nobunaga asks Yūto to cover for him selling dōjinshi for one of his friends' dōjin circles at an upcoming event for Nocturne Girl's School Lacrosse Club. Yūto asks Haruka to accompany him, who is overjoyed at the prospect of helping out an already established circle. Yūto and Haruka continue their work on Haruka's illustration book of the Nocturne Girl's School Lacrosse Club lead character Haruna, though the day of the event Haruka's book is not selling. Nobunaga gives Yūto some advice, telling him that half the enjoyment is actually making the dōjinshi and Yūto realizes there are more important things that the book selling or not. Yūto goes back to Haruka and starts promoting Haruka's book, and eventually three people end up buying it.