In Narnia, 1300 years have passed since the Pevensie siblings went home to Earth. Caspian (Ben Barnes), a Telmarine Prince, is awakened by his mentor Doctor Cornelius (Vincent Grass) with the news that his aunt has just given birth to a son and his life is now in danger. His Uncle Miraz (Sergio Castellito) will surely try to kill him to be King. Cornelius gives him Queen Susan’s ancient horn and tells him how to summon help through its magic. Caspian flees, pursued by fierce Telmarine soldiers (the entire race is descended from pirates). He falls off his horse and encounters two Narnian dwarfs—Trumpkin (Peter Dinklage) and Nikabrik (Warwick Davis)—and Trufflehunter the Badger (voice of Ken Stott). Trumpkin is captured by soldiers and the others save Caspian, who blows the magic horn to summon help. The four Pevensie children are at the Strand Tube Station in London, waiting for the train to boarding school. They are Peter (William Mosely), Susan (Anna Popplewell), Edmund (Skandar Keynes), and little Lucy (Georgie Henley). In this world, only one year has passed since they returned from Narnia. As the train pulls into the station, the world seems to tear itself apart and they are pulled into Narnia. They discover that their castle, Cair Paravel, is in ruins. They save a bound and gagged Trumpkin from being drowned and take him with them.
Nikabrik and Trufflehunter lead Prince Caspian to the Dancing Lawn, where the remaining old Narnian creatures have gathered. Caspian convinces them to help him win the throne. They meet up with the Pevensies and Trumpkin and journey to Aslan’s How, a great underground hall built over the stone table on which the lion was sacrificed and resurrected in the previous movie. Lucy wants to wait for Aslan’s help, but Peter decides to attack Miraz’s castle. It does not go well. They fail to secure the castle and many Narnians are killed.
Nikabrik says he has a plan for Caspian to regain his throne. A hag summons the ghost of the White Witch (Tilda Swinton), killed in the first movie. From inside a wall of ice, she tries to convince Caspian to give her a drop of blood, which will set her free. Peter, Edmund, and Trumpkin arrive, kill Nikabrik, and shatter the ice. Miraz and his army arrive at Aslan’s How. Peter challenges Miraz to a duel, to give Lucy time to find Aslan. Peter wounds Miraz and gives his sword to Caspian, who spares Miraz and vows to give Narnia back to the Narnians. One of Miraz’s generals suddenly kills Miraz and blames the Narnians, causing the Telmarines to attack, and there is a great battle.
Lucy has found Aslan (voice of Liam Neeson) in the woods. He awakens the trees and the forest attacks the Telmarines, then he summons a river god to wipe them out. The few remaining soldiers surrender. Caspian becomes King, and with Aslan’s help begins to restore the Kingdom. The Pevenzies return to England.
This movie has a much darker tone than the first. The attack on Miraz’ castle was not in the book but was added for more action. In the film, Susan is given a bigger role in battle than she had in the book. She was supposed to be an expert archer, after all. And she was given just a bit of romance with Prince Caspian. Ben Barnes modeled Prince Caspian’s accent on Mandy Patinkin’s performance as Inigo Montoya in The Princess Bride. Reepicheep, the swashbuckling and fearless mouse, a major character in Voyage of the Dawn Treader, first appeared here, voiced in this movie by Eddy Izzard. He advised the animators to watch Errol Flynn movies. Nikabrik is descended from Ginarrbrik, the White Witch’s dwarf in the first movie. The costumes of the Telmarines were based on El Greco paintings. The bridge built by the Telmarines was based on the one that Julius Caesar built over the Rhine. His took only ten days to build instead of forty, but he had the Roman Army.