There is a key even in another world. There are many places where unlocking skills can be used, such as dungeon treasure chests, hidden doors, and prisons. From such a different world thief guild, a scout comes to Kii Jinroku (Rock), a free locksmith. Rock, who was once trained as a brilliant key master, unlocks a different world with his own technology! With the guild’s fox-eared girl Islay as a disciple, Rock continues to receive requests for keys today … ..