Ikai Tettai Parabellum

High schooler Koma Higurashi falls asleep on the train on his way home and wakes at an unfamiliar station. There, he encounters Mayuru, a girl who has gone missing, just as an unexpected shootout breaks out. Amid the chaos, Koma realizes he has wandered into a mysterious alternate realm. The opening follows his sudden arrival in this strange place and the events that bring him face-to-face with Mayuru.