College student Sorawo Kamikoshi wanders into the Otherside, a folklore-haunted mirror world she reaches through a door hidden in an abandoned building, and nearly becomes prey to one of its creatures before Toriko Nishina pulls her out. Toriko, an experienced explorer searching for a missing friend, recruits Sorawo as a partner for repeat trips into the Otherside, where urban legends and cryptids are real and dangerous. This manga adapts the light novel series of the same story.