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 transition to university life brings new stability: he's settled into a relationship with Mai Sakurajima and they've enrolled together in Kanazawa. But peace doesn't last long. A chance encounter with a girl dressed as Santa in the middle of summer becomes the first thread in an increasingly tangled mystery. Precognitive dreams, an unsigned internet musician, and unexplained phenomena tied to social media begin surfacing around girls struggling with invisible emotional fractures. Puberty Syndrome, the strange supernatural affliction Sakuta's encountered before, continues its strange work on those caught between adolescence and adulthood. As reality bends around their psychological turmoil, Sakuta finds himself pulled back into the role of reluctant investigator. Each phenomenon carries weight, each girl carries secrets, and nothing about these cases feels coincidental. The line between dreams and waking blurs. The internet age amplifies isolation even as it connects everyone. What begins as curiosity becomes necessity when the mysteries start converging, threatening not just those affected but potentially everything Sakuta has worked to protect.