After Tova Sullivan's husband died, she began working the night cleaner shift at the Sowell Bay Aquarium. Ever since her eighteen-year-old son, Erik, mysteriously vanished on a boat over thirty years ago keeping busy has helped her cope. One night she meets Marcellus, a giant Pacific octopus living at the aquarium who sees everything, but wouldn't dream of lifting one of his eight arms for his human captors – until he forms a remarkable friendship with Tova.