Mei Hatsume, the girl from support course, had made a time-travel portal and decided the oblivious present day Class 1-A would be the perfect people to test it on.

Class 1-A entered and everything looked normal, however as they entered their classroom, it was filled with other students. The weird part was that the students looked like another version of them or a kid born from a relationship they have in the future, like they were their children from the future. Of course they were, it was a time travel after all. Class 1A’s future offspring had been teleported into their classroom.