A year has passed since the Pevensie children returned from Narnia, where they reigned as queens and kings for many Narnian years. While at a train station en route to their new boarding schools, the children feel themselves being pulled by an invisible force and suddenly find themselves in a thick forest. After walking along a nearby beach for hours, the children realize they are on an island. Tired and hungry, the children drink water from a stream and look for food. Finally, they find an apple tree and an old stone wall that surrounds a grassy open space. They realize that at some point the island must have been inhabited.

The children believe that the garden used to be the courtyard of an ancient castle and agree that being there gives them a strange feeling. Peter notices many parallels between the ruins and their former castle, Cair Paravel, which was at the mouth of a large river. As night falls, the children forage for firewood and apples and set up a camp. Susan finds a golden horse chess piece by the well, and the children recall how they used to play with such pieces at Cair Paravel.