Summer vacation is here. Susan and Peter, who have grown up, live in the United States with their parents, while Lucy (Georgie Henley) and Edmund (Skandar Keynes) live with their aunt. They are very reluctant to do so because there is a cousin named Eustace (Will Poulter) who is always annoying. One day, an oil painting depicting a ship sailing on the sea comes to life, and the water keeps overflowing. Lucy, Edmund and their little cousin are swept into the vast ocean of the Narnia world. Fortunately, the three are rescued by Prince Caspian (Ben Barnes) on the ship. It turns out that he is on his way to find the old ministers of the kingdom, so the four of them embark on a new adventure together. This film is the third episode of the "Chronicles of Narnia" series, adapted from the fourth novel of the same name, "The Voyage of the Dawn Treader".