Eighteen-year-old Maddy is being treated for severe combined immunodeficiency, an immune disorder that prevents her from leaving her home and interacting with others. Her mother, Pauline Whittier, takes care of her with the help of her nurse Carla, who has taken care of Madeline for 15 years. Only Pauline, Carla and Carla's daughter, Rosa, are allowed in the home. Maddy yearns to see the world, particularly the ocean.