Sakuta and Mai are comfortable enough with each other now that the real story isn't about falling in love, it's about staying in love while the world keeps trying to break them apart. The show treats that as harder than the confession ever was. Every Puberty Syndrome case becomes a test of whether they actually know each other, not whether they can save each other, and that shift from rescue fantasy to genuine partnership costs something, it asks you to watch people you care about fail at understanding each other and have to keep trying anyway.

Sakuta Azusagawa's high school days are over, and he now attends a university in Kanazawa-hakkei with his girlfriend Mai Sakurajima, an actress famous across Japan. While settling into campus life and meeting new people, he encounters a girl wearing an out-of-season miniskirt Santa costume, who seems surprised that he can see her. She calls herself Toko Kirishima and claims to give Puberty Syndrome to others, the strange phenomenon said to arise from an unstable state of mind. Nodoka Toyohama asks for his help when her Sweet Bullet bandmate Uzuki Hirokawa begins behaving strangely under the pressure of sudden popularity and talk of a solo career. While Sakuta looks for an answer, another case slowly surfaces, amid precognitive dreams, an anonymous singer online and poltergeist rumors on social media. The result is a supernatural mystery drama with romance, centered on girls whose hearts are unsettled.