Patema Inverted

In 2067, scientists attempt to harness energy from gravity. The gravity reverses, however, and nearly everyone and everything is sent flying from Earth.

Years later, Patema is a respected teenager who lives in an underground society - Aiga- which imposes rules to keep its members away from "danger zones" that surround the community. Inspired by her friend Lagos, who has mysteriously disappeared, Patema explores the tunnels. One day, she is startled by a figure that walks on the ceiling while exploring and falls into the shaft below. Read more on Wikipedia.