Even after leaving Fujisawa for Ogaki, not one person remembered anything about Mai Sakurajima. Sakuta and Mai return to school together, but even there they hear from Sakuta's friend Rio Futaba that nobody at school outside of her has any recollection about Mai. At the same time, Sakuta hears of a theory that losing memories concerning Mai is based on a certain action taken, and struggles so that he doesn't lose his memories of her. And seeing Sakuta act as such, Mai makes a certain decision of her own as well...

Soon after Mai's "puberty syndrome" is resolved, Sakuta encounters another strange phenomenon without respite. Day after day, it is the same day for Sakuta and there is no tomorrow. When he consults Rio, she raises the possibility of "Laplace’s demon" -- that someone may be repeating and redoing a day.

Because of the misunderstanding that she was dating Sakuta, Tomoe is able to resolve the agonizing situation of being asked out by the guy her friend is in love with. She pleads with Sakuta to continue acting like they are dating. Despite feeling indebted to Mai, Sakuta could not leave Tomoe alone as she was fearing that she would lose her presence within her class. So, he reluctantly agrees to play the role of Tomoe's fake boyfriend for a while.

It is now the last day of the first term, the promised day when pretending to be dating Tomoe ends. It seems as though everything has finally been resolved, but…