[4] It was the fourth of seven novels published in The Chronicles of Narnia (1950–1956), but became volume six in recent editions sequenced in chronological order to Narnian history.

Aslan the lion sends two children from England to Narnia on a mission to resolve the mystery: Eustace Scrubb, from The Voyage of the Dawn Treader, and his classmate, Jill Pole.

Eustace Scrubb, now a reformed character following the events of The Voyage of the Dawn Treader, encounters his classmate and new friend Jill Pole at their school, Experiment House, where they are miserable.

He charges Jill with helping Eustace find King Caspian X's son, Prince Rilian of Narnia, who disappeared some years earlier.

Caspian's Lord Regent Trumpkin the dwarf, now very elderly and deaf, provides Jill and Eustace with rooms in Cair Paravel, but on the advice of Glimfeather the Owl, they make no mention of their quest.

Glimfeather summons them to a Parliament of his fellow talking owls, who explain that Prince Rilian disappeared a decade earlier while searching for a large green serpent that had killed his mother.

Jill and Eustace are flown to the marshes on the northern edge of Narnia where they meet their guide, Puddleglum, a gloomy but stalwart Marsh-wiggle.

Hungry and suffering from exposure, they meet the Lady of the Green Kirtle accompanied by a silent knight in black armour.

They are found by an army of underground-dwelling earthmen, who take them aboard a boat across the subterranean Sunless Sea to the city ruled by the Lady of the Green Kirtle.

Free from enchantment, he thanks them and declares that he is indeed the vanished Prince Rilian, kept underground by the Lady of the Green Kirtle as part of her plot to conquer Narnia.

The Green Lady returns and tries to bewitch them all into forgetting who they are, but the barefoot Puddleglum stamps out the enchantress's magical fire and breaks her spell.

The gnomes, who had also been magically enslaved by the Lady, are now freed by her death and joyfully return to their home even deeper in the earth: a land called Bism.

The kingdom goes on to have many happy years, but Puddleglum "often pointed out that bright mornings brought on wet afternoons and that you couldn't expect good times to last."

Lewis Company announced that it had entered into an agreement with The Mark Gordon Company to jointly develop and produce The Chronicles of Narnia: The Silver Chair, following the film series' mirroring of the novel's publication order (in contrast to Walden Media's initial pushing for The Magician's Nephew during planning for a fourth film).