A character in C.S. Lewis' Chronicles of Narnia, sister to Peter, Edmund, and Lucy Pevensie.
The second-oldest child, when she first appeared in The Lion, the Witch, and the Wardrobe she was sensible and slightly unimaginative. Like Peter, she did not believe her sister's claims to have found a door to the land of Narnia in an old wardrobe. She eventually accompanied the others there, however, and witnessed the battle between the forces of Aslan and the White Witch. While there Father Christmas gave her a Gift: a magic horn which would summon help wherever it was blown. She and her siblings became Kings and Queens of Narnia and reigned for many years.
During that time she caught the attention of the Calormene Prince Rabadash, and journeyed to the capital of Calormen, Tashbaan, with King Edmund. Upon realizing that Rabadash would not take "no" for an answer, they and their entourage fled the city. Rabadash and 200 horse attacked the Narnian ally Archenland in retaliation, but were turned back. (The Horse and His Boy)
Susan and her brothers and sister eventually returned to our world, magically returning to their proper ages. Meanwhile in Narnia 1,000 years had passed, and the cruel King Miraz reigned. His nephew, Prince Caspian, and his rebellion blew Susan's ancient horn -- and the four of them were transported back to Narnia. At the end of their adventure, Aslan told her and Peter that they would never return to Narnia; they were too old. (Prince Caspian)
Over the successive years, Susan forgot about Narnia. Whenever the subject came up with the other Friends of Narnia, she dismissed it as a silly game they had played when they were children. Of her, Polly Plummer said:
I wish she would grow up. She wasted all her school time wanting to be the age she is now, and she'll waste all the rest of her life trying to stay that age. Her whole idea is to race on to the silliest time of one's life as quick as she can and then stop there as long as she can.