In central Tokyo, a young man Sosuke aspires to be a manga artist. His current work is about a battle between a hunter and a Japanese wolf. He can’t draw the extinct wolf well, neither develop the story. One winter’s day, Sosuke finds an animal’s skull while digging foundations at a construction site. He is a day laborer to make a living. Is it a Japanese wolf’s skull? Sosuke takes it home without permission. Looking on the Internet, he can’t get a clue if this is a skull of a Japanese wolf. His interest peaks and he sneaks into the construction site at night to find other pieces of bones, which may help him draw the Japanese wolf. Unusual in winter, fireworks display tonight. Without finding any bones, Sosuke leaves the construction site. Disappointed, he bumps into a mysterious woman Midori and unintentionally injures her. Midori is looking for her dog, missing for a week. Feeling sorry for her injury, Sosuke helps to look for the dog together. Wandering around a quiet town, wondering why the fireworks do not start, he travels through time into Tokyo’s past lying underground.