In The Voyage of the "Dawn Treader," Lewis greatly expands the size of Narnia's known world, sending his characters across a vast expanse of ocean and to many islands, until they reach the Last Wave and the End of the World, beyond which is Asian's country, high atop and beyond sheer cliffs. Once the ship reaches the Lone Islands, soon after picking up Lucy, Edmund, and Eustace, it sails from the island, heading roughly southeast until reaching the Last Wave.

A Narnian king has not visited the Lone Islands for hundreds of years, and its government has fallen into corruption and there is a slave market in Narrowhaven, the capital of the province. When Caspian asserts his authority, he bans slavery, removes the corrupt government, and appoints Lord Bern a duke and governor of the Lone Islands. Bern is one of the seven faithful lords that the usurper...