In a word: This is a time-travel story.
Two sentences: This is a time-travel story, and the heroine is Kitajima Roku.
Three sentences: This is a time-travel story, the female protagonist is Kitajima Roku, and the male protagonist is Skylark.
Four sentences: This article is a happy rant, interspersed with the plot of the tutoring cartoon, and various tricks, please bring 10+20+ blue waves, it is over.