Tokyo was flooded thanks to the bubbles that started floating down from the sky, and some of it still exists. Parkour tournaments were held as various young people defied the restrictions and never cared if something was wrong. The Blue Blazes was a team of parkour talents, and they were pretty much a bit of an underdog team.

One day, while practicing for an upcoming parkour tournament alone, Isozaki noticed a clump of bubbles suddenly sticking to each other. He parkoured his way to check it out, but as soon as he stepped on a few bubbles, the last bubble popped. He fell with a soft shout, into the flooded streets below. This was it, for him...he could probably swim, but he couldn't. Then...he saw someone in the waters.