Troubled by a strange recurring dream and mourning the loss of her beloved father, nineteen-year-old Alice Kingsleigh attends a garden party at Lord Ascot's estate, where she is confronted by an unwanted marriage proposal, to Hamish Ascot, and the stifling expectations of the society in which she lives. Unsure of how to reply, she pursues a rabbit in a blue waistcoat, and accidentally falls into a large rabbit hole, from which she emerges in a forest, where she is greeted by the White Rabbit, the Dormouse, the Dodo, the Talking Flowers, and Tweedledee and Tweedledum. They argue over her identity as "the right Alice", who must slay the Red Queen's Jabberwocky and restore the White Queen to power, as foretold by Absolem the Caterpillar. The group is then ambushed by the Bandersnatch and a group of playing-card soldiers led by the Knave of Hearts. Alice, Tweedledum and Tweedledee escape into the woods, while the Knave steals the Caterpillar's scroll and the Dormouse leaves the others, with one of the Bandersnatch's eyes. Tweedledum and Tweedledee are then captured by the Red Queen's Jubjub Bird.
The Knave informs the Red Queen that Alice threatens her reign, and the soldiers and Bayard the Bloodhound are ordered to find Alice immediately. Meanwhile, the Cheshire Cat guides Alice to the March Hare and the Hatter. The Hatter helps Alice avoid capture by allowing himself to be seized instead. Later, Alice is found by Bayard the Bloodhound; but Alice insists upon helping the Hatter. At the Queen's citadel, the Red Queen is unaware of Alice's true identity and therefore welcomes her as a guest. Alice learns that the Vorpal Sword, the only weapon capable of killing the Jabberwocky, is locked inside the Bandersnatch's den. The Knave crudely attempts to seduce Alice, but she rebuffs him, and a jealous Red Queen orders Alice beheaded. Alice obtains the sword and befriends the Bandersnatch by returning its eye; escapes on the back of the Bandersnatch; and delivers the sword to the White Queen. The Cheshire Cat saves the Hatter from the executioner, and the Hatter calls for rebellion against the Red Queen. The rebellion is quickly put down by the Jubjub bird, but the resistance flees to the White Queen's castle, and both armies prepare for battle. Absolem advises Alice to fight the Jabberwocky, before completing his transformation into a pupa.
On the appointed day, the White and Red Queens gather their armies on a chessboard-like battlefield and send Alice and the Jabberwocky to decide the battle in single combat. Encouraged by the advice of her late father, Alice beheads the Jabberwocky, and the White Queen sends the Red Queen and the Knave into exile. After the Hatter performs a celebration dance called Futterwacken, the White Queen gives Alice a vial of the Jabberwocky's purple blood, which will take her home. In England, Lord Ascot takes Alice as his apprentice with the idea of establishing oceanic trade routes to China. As the story closes, Alice prepares to set off on a trading ship. A light-blue butterfly lands on her shoulder, which Alice identifies as Absolem.