Anime Crossover: Why Are Yukino and the Others Taking This Seriously?

After transferring to Sobu High, Hoshino Yu hoped to quietly enjoy his high school life. That is, until he joined the Service Club and unexpectedly found himself caught up in Yukinoshita Yukino's social troubles, while also becoming the first reader of light novelist Kasumigaoka Utaha. Helping his senpai revise her work, writing songs with the light music club, assisting the student council with campus events... He thought these were just ordinary encounters of youth. So why was Yukino looking at him with an increasingly complicated expression? Why had Utaha started inviting him over so often to discuss “life”? And why was Iroha Isshiki, who was always joking around, gradually becoming so serious? Wait... Are they all serious about this?