Kuro is asked by Ramune to come to a place called “Mysterious Tool Shop Akatsuki”. From the outside, it looks like an antique shop. But on the inside, they’re selling “mysterious tools”. Kuro is curious about the making of “mysterious tools” after getting acquainted with the shop owner, Nico, and his great-grandmother, Ayame, a 112-year-old who appears as a little girl. Suddenly, a strange man appears before all of them.