Various types of ancient creatures suddenly appear in the modern world.

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.

A gifted runner trains a determined but unskilled classmate, unaware he's creating a rival who will challenge him on the track for years to come.

Kazuki Tsukigase is a high school boy who carries a certain secret. In search of a place where no one knows him, he enrolls at Sakijima High School on a remote island. On Sakijima, there is a place known as the "Cove of Spiriting Away." One early summer day, Kazuki finds a girl lying unconscious in the cove. The girl—Nanao, 16 years old—later regains consciousness in the hospital, but her identity remains unknown. What is the meaning behind the word "1974" that she murmured?