Fugitives of Chaos — John C. Wright

Fugitives of Chaos is a tale about five orphans raised in a strict British boarding school who begin to discover that they may not be human beings. The students at the school do not age, while the world around them does. The orphans have been kidnapped from their true parents, robbed of their powers, and raised in ignorance by superbeings no more human than they are. They are surrounded by pagan gods and fairy queens, Cyclopes, sea- monsters, witches, and things even stranger.

The children must experiment with and learn to control their abilities in order to escape their captors. Something very important must be at stake in their imprisonment. This is the story of their escape.