Aslan proclaims him King Edmund the Just, but in the letter sent to Miraz in the novel Prince Caspian he styles himself "Duke of Lantern Waste and Count of the Western March, Knight of the Noble Order of the Table".

He walks some distance into the forest, convinced that he will find Lucy, but instead he meets the White Witch (who introduces herself as the Queen of Narnia) and eats some enchanted Turkish delight.

As a result, he promises the Witch that he will bring his siblings to her castle, not knowing that she intends to kill them all to prevent the fulfillment of a Narnian prophecy.

When they all enter Narnia, the children are taken under protection of Mr and Mrs Beaver, but while the others are having an in-depth conversation about the arrival of Aslan, Edmund sneaks away to the White Witch's castle, where he expects to be made a prince and later a king.

Edmund realises the full extent of her evil on their journey when she turns a group of creatures enjoying a feast provided by Father Christmas to stone.

He is saved from death by the timely arrival of reinforcements led by Aslan, and by Lucy, who gives Edmund a dose of a magic cordial which can quickly heal any injury.

Mistaking Shasta for the missing prince Corin Thunderfist of Narnia's ally Archenland, Edmund scolds the young boy for running off and making everyone worry.

The Narnians manage to escape, which leads Rabadash to convince his father the Tisroc that they should take Narnia by invading Archenland.

Edmund, Shasta, and Corin's father, King Lune of Archenland, lead the fight against the Calormene army and defeat them.

Also in the film, he stops the White Witch from being brought back from the dead by forcing his sword into the ice wall through which she is trying to re-enter Narnia, smashing it.

They are rescued and brought on board the Dawn Treader, where they are reunited with King Caspian, who is on a quest to search for the missing Lords that his uncle had sent to explore other lands some years before.

Like his brother and younger sister, he is killed in the train crash and is transferred to Aslan's country, where they all live forever.