Lucy and Edmund Pevensie are stranded in Cambridge, living in the house of their obnoxious cousin Eustace, while the grown-ups Susan and Peter are living in the USA with their parents. When a painting of a ship sailing on the sea of Narnia overflows water in their room, Lucy, Edmund and Eustace are transported to the ocean of Narnia and rescued by King Caspian and the crew of the ship The Dawn Treader.