Rose is a twelve-year-old girl spending her summer at a familiar beach town. She stands on the precipice of adolescence, feeling a mix of curiosity and confusion about the older teenagers around her. She acts more mature than she actually is, sometimes clashing with her younger friend while trying to process the heavy tension between her parents.

Windy is a ten-year-old girl who spends her summers at the beach. Adopted by an older mother, she leads an eclectic life filled with music and swimming. She holds a lighter perspective on the world compared to Rose, viewing the older teenagers' drama with amusement rather than reverence. She refuses to conform to social expectations about growing up.

Alice is Rose's mother who arrives at Awago Beach seemingly unhappy and withdrawn. She avoids the water entirely. She maintains an emotional distance from her family, creating a heavy tension within the cottage that deeply affects her daughter and husband.

Evan is Rose's father, providing a sense of stability for his daughter. He tries to keep the vacation pleasant with jokes, but he struggles constantly with his wife's distant mood. His frustration with the family dynamic occasionally boils over into arguments.

Jenny is a local teenager who works at the Heritage Huron Village. She spends her free time hanging out around Awago Beach and dating Duncan. Rose frequently observes and judges her actions from afar, projecting her own ideas of adulthood onto the older girl.

Evelyn is Windy's adoptive mother and a professional massage therapist. She is a gentle woman who provides a comforting presence for both the children and the adults around her. She maintains a calm, nonjudgmental attitude that sharply contrasts with the tension in the Wallace household.

Duncan is the eighteen-year-old clerk at Brewster's, the local convenience store. He spends his shifts making fun of younger kids and flirting with Jenny. He remains careless about his responsibilities and oblivious to the fact that twelve-year-old Rose closely watches his behavior.

Jodie is Alice's sister and Rose's maternal aunt. She visits the beach house to celebrate a birthday. She brings a loud, somewhat childish energy to the otherwise quiet family vacation, often failing to notice her sister's foul mood.

Daniel is Jodie's husband and Rose's uncle. He is a boisterous man who enjoys drinking beer on the beach. He acts immaturely and eventually clashes with Alice when he tries to force her to participate in water activities against her will.