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.

Upon inducing a case of "Puberty Syndrome" where two copies of herself exists, Rio ends up staying at Sakuta's house for the time being. Meanwhile, "the other Rio" has been busy posting various unexpected photos on social media. After being informed about these activities by his classmate, Saki Kamisato, Sakuta decides to have a chat with "the other Rio." As he learns more about each of the Rio-s in hopes of discovering the reason for "the other Rio’s" actions and possibly a cure for her "Puberty Syndrome," Sakuta begins to realize the troubles each of them carries...

Unable to deal with a commercial filming well as the actress Mai Sakurajima, Nodoka gradually starts to feel a strong sense of inferiority. As their body-swapped lives continues on, the day arrives where Mai must perform in Nodoka's pop idol group "Sweet Bullet". Sakuta and Nodoka attend the concert as they were given tickets...