Shōjo Yoshitsuneden

An ordinary second-year high school student is on a class field trip to Kyoto, the heart of traditional Japanese culture. One night, as a penalty for losing a game to some of his friends, he is forced to attempt to sneak into the girls' bathing area to peep on them. However, he is caught, and falls into the bath, suddenly being surrounded by a strange light. When he comes to, he finds that he has somehow been transported back in time to the late 12th century, at the twilight of the Heian period ...