Children of the Sea

Ruka Azumi spends her summer break obsessively practicing handball, using it as an escape from her strained relationship with her alcoholic mother. But after an incident gets her kicked off the team, she has nowhere to turn until she visits the aquarium where her father works. There, she meets Umi-a strange boy raised by dugongs who is confined at the facility due to his body’s unusual dependence on water. Despite his odd background, Ruka quickly befriends Umi, and their bond deepens when Sora, Umi’s equally enigmatic brother, joins them. As the trio dives into the mysteries of the ocean, they discover a breathtaking underwater realm and learn of a strange global "festival" that every sea creature seems to be anticipating.