Tokyo Undercover

According to statistics, for every three ordinary Japanese high school students, there is one time traveler. Most of them are light novel authors, academics, cartoonists, etc. Among them are ninjas, Taoist priests, monks and other side professions. Their parents are both dead, They have a girl and a house, They come with their own "system"; What they like to do most is: talk about studying hard and not fall in love. In fact, they start a harem and one is more diligent than the other. Kotomine Tomoya originally thought that he was one of them, Until he met the emergence of the "Shinsengumi Second Generation" whose creed is "annihilation of time travellers".