Yuuko Sera

Shy outcast Kokoro has been avoiding school for weeks when she discovers a portal in her bedroom mirror. She reaches through and finds herself transported to an enchanting castle where she is joined by six other students. When a girl in a wolf mask explains that they have been invited to play a game, the teens must work together to uncover the mysterious connection that unites them. However, anyone who breaks the rules will be eaten by a wolf.

Ruka is a young girl whose parents are separated and whose father works in an aquarium. When two boys, Umi and Sora, who were raised in the sea by dugongs, are brought to the aquarium, Ruka feels drawn to them and begins to realize that she has the same sort of supernatural connection to the ocean that they do. Umi and Sora's special power seems to be connected to strange events that have been occurring more and more frequently, such as the appearance of sea creatures far from their home territory and the disappearance of aquarium animals around the world. However, the exact nature of the boys' power and of the abnormal events is unknown, and Ruka gets drawn into investigating the mystery that surrounds her new friends.

Goro briefly returns to Japan after a triumphant campaign in the US. He is heading towards Fukuoka where he played baseball when he was a fifth grader. Having just moved into a new town, this is where Goro faced a critical point in his life.