Inverted Patema: another side

A floating ring has been passed down through Mikko's family for generations. Her grampa told her that the ring bears a promise of reuniting with lost ones who departed to the “other world“. Mikko explores her world—an endless network of tunnels—in hopes of finding the “other world” one day…

Another story that goes upstream of the main anime movie and depicts the daily life and discoveries of a certain girl in the underground world!!