Twelve-year-old Caitlin lives alone with her mother - a docker at the local container port - in subsidised housing next to an airport in Seattle. Each day, while she waits to be picked up after school, Caitlin visits the local aquarium to study the fish. Gazing at the creatures within the watery depths, Caitlin is transported to a shimmering universe beyond her own. 

When she befriends an old man at the tanks one day, who seems as enamoured by the fish as she, Caitlin cracks open a dark family secret and propels her once-blissful relationship with her mother towards a precipice of terrifying consequence.