In The Lion, the Witch, and the Wardrobe, the first book in the Chronicles of Narnia series, siblings Peter, Susan, Edmund, and Lucy are transported to the fantasy world of Narnia through a magical wardrobe. Once there, they find themselves in a battle between good and evil, as the the wicked White Queen strives to keep the kingdom under her control. The siblings end up defeating the queen and become rulers of Narnia themselves. The book is an allegory, with the lion Aslan representing God and the Queen representing evil.
In 1940, four siblings– Peter, Susan, Edmund, and Lucy Pevensie – are among many children evacuated from London during World War II to escape the Blitz. They are sent to the countryside to live with professor Digory Kirke. Exploring the professor's house, Lucy finds a wardrobe which doubles as a magic portal to a forest in a land called Narnia. At a lamppost oddly located in the forest, she meets Tumnus, a faun, who invites her to tea in his home. There the faun confesses that he invited her not out of hospitality, but with the intention of betraying her to the White Witch. The witch has ruled Narnia for years,using magic to keep it frozen in a perpetual winter. She has ordered all Narnians to turn in any humans ("Sons of Adam" or "Daughters of Eve") they come across. But now that he has come to know and like a human, Tumnus repents his original intention and escorts Lucy back to the lamppost.
Lucy returns through the wardrobe and finds that only a few seconds have passed in normal time during her absence. Her siblings do not believe her story about another world inside the wardrobe, which is now found to have a solid back panel.
During a game of hide-and-seek on some days later, Lucy again passes into Narnia. This time her brother Edmund chances to follow her. He meets Jadis, who calls herself Queen of Narnia. When she learns that he is human and has two sisters and a brother, she places an enchantment on him. She urges him to bring his siblings to her castle, promising in return to make him her heir. When Lucy and Edmund return together through the wardrobe, Edmund realizes that the queen he met and the witch Lucy describes are one and the same. He denies to the others that he has been in Narnia at all. Peter and Susan are puzzled by Lucy's insistence, and consult the Professor, who surprises them by taking Lucy's side in the debate of Narnia's existence.
Soon afterward, all four children enter Narnia together after hiding in the wardrobe to avoid the professor's dour housekeeper, Mrs. Macready. Remembering the winter cold ahead, they take coats from the wardrobe before exploring. Lucy guides them to Tumnus's cave, but they find it ransacked, with a notice from Jadis (the White Witch) proclaiming his arrest for harbouring humans.
A talking beaver intercepts them, proves himself a friend, and hides the children in his den. There, he and Mrs. Beaver tell them of a prophecy that Jadis's power will fail when two Sons of Adam and two Daughters of Eve fill the four thrones at Cair Paravel. Aslan, the great lion and the rightful King, has been absent for many years but is now "on the move again" in Narnia.
Edmund steals away to Jadis's castle, which is filled with statues of Narnian victims she has turned to stone. Jadis is furious when Edmund appears alone and angrier still to learn that Aslan may have returned. She takes him on her sledge to catch the others or to reach Aslan's court before them.
Meanwhile, Mr Beaver realises that Edmund has betrayed them, and they set off at once to seek Aslan at the Stone Table. As they travel, the Witch's spell over Narnia begins to break: Father Christmas (who has not been seen in Narnia for a hundred years) arrives with magical presents: a sword for Peter, a horn and a bow with arrows for Susan, a knife and a bottle of healing cordial for Lucy. The snow melts, and winter ends. Aslan welcomes the children and the Beavers to his camp near the Stone Table. Upon hearing Edmund's situation, he orders a rescue party of loyal Narnians.
After much hardship at the hands of the Witch and her sledge driver, Edmund is rescued from their camp and reunited with his siblings. Jadis approaches in truce to parley with Aslan. She insists that, according to "deep magic from the dawn of time", she holds the right to kill Edmund following his treason. Aslan bargains with her privately and she renounces her claim.
That evening, Aslan secretly returns to the Stone Table, shadowed by Susan and Lucy. Upon noticing them, Aslan welcomes their company but warns them not to interfere with what is about to happen. He has traded his own life to the witch for Edmund's, and the girls watch as Jadis oversees his shaming before her underlings. She orders Aslan tied to the Stone Table, shaved and muzzled; and she administers the killing blow herself.
Confident now of victory, the Witch leads her army away to battle. Susan and Lucy remain weeping over Aslan's abandoned body. They un-muzzle him and see mice gnaw away his bonds. The Stone Table breaks and Aslan is restored to life. He tells Lucy and Susan that Jadis was unaware of the "deeper magic from before the dawn of time" that will resurrect an innocent killed in place of a traitor.
Aslan carries Lucy and Susan on his back as he hurries to Jadis's castle. He breathes upon the stone statues in the courtyard, restoring them to life.
Meanwhile, Peter and Edmund lead the Narnians against Jadis, and Edmund is seriously wounded. Aslan arrives with the former statues as reinforcements. The Narnians rout Jadis's supporters, and Aslan kills Jadis. Aslan breathes life into those Jadis has turned to stone on the battlefield, and Lucy uses her magic cordial to revive the wounded, starting with Edmund. The Pevensie children are crowned kings and queens of Narnia at Cair Paravel. Soon afterward, Aslan slips away and disappears.
Fifteen years later, the four rulers chase a wish-granting white stag through the forest whereupon they rediscover the lamppost. They soon find their way not through branches but coats. They come back through the wardrobe in the Professor's house and are suddenly children again, dressed in their old clothes. Almost no time has passed in the real world, despite their many years in Narnia.
The four children consult the Professor. He forgives them the absence of the four coats they stole, and hints that theirs would prove not to be the first adventure in Narnia, nor by any means the last.