See in Ao Vol. 1

 青

There's a story that must be told - hidden beneath the beautiful blue waves of this ocean city. Kyoya, a teacher at the Underocean school, lost his memory in an unfortunate accident that took place 3 years earlier and since then has been taken of by a beautiful young girl named Miyu. It's natural that Miyu would become the center of all his wildest fantasies, but Yumi has a suspicious feeling that there may be more to Kyoya than he lets on.

See in Ao Vol. 2

 青

Amazingly, it turns out that the only real reason Yumi enrolled at the Underocean school was because of the fact that Kyoya was there. Unfortunately, after Miyu's death... Kyoya's attentions have already turned to Shinjun, another young teacher at the school.