In Tokyo, where gravity no longer applies, a boy and a girl fall in love with each other... The story begins in Tokyo, where bubbles rain down from all over the world and the law of gravity breaks down. Completely cut off from the outside world, Tokyo has become a playground for a group of young orphans. They form groups and jump between buildings in parkour battles. Hibiki, a young player who has made a name for himself with his dangerous gaming style, slips and falls into a sea that reverses gravity, but is rescued by a girl named Shi who possesses a mysterious power. Then, the two hear a unique sound that no one else can hear. Why does Shi appear in front of Hibiki? The two meet and uncover a truth that could change the world.