Prince Caspian (Chronicles of Narnia)

The Chronicles of Narnia: Prince Caspian, Softcover

In "Prince Caspian," Peter, Susan, Edmund, and Lucy are returning to boarding school when they are summoned from the dreary train station (by Susan's own magic horn) to return to the land of Narnia- the land where they had ruled as kings and queens and where their help is desperately needed.

C.S. Lewis