The Kids of the Sea (2021)

Polly gives her mentally handicapped brother, Kyle, who is allergic to milk, a bottle of milk. However, their mother, Brooke, comes home and swaps the bottle. She beats Polly and doesn't care about her bleeding hands. The other day, Polly takes Kyle to the beach and tells him to go back to the see. Suddenly, it brings her back to the memory of playing the game "The Kids of the Sea" in their childhood.