Incarceron is prison, but unlike any prison you have ever heard of. It is a living complex of cells, cities and wilderness that is continually shifting. Only the Warden of Incarceron knows where the prison is located. Having been permanently sealed shut for over 160 years, legend has it that only one man has ever escaped. And Finn hopes to be number two.
Seventeen-year-old Finn the Starseer is a prisoner of Incarceron but doesn't remember his childhood. Everyone says he is a "cellborn" but Finn has flashs of a birthday cake and believes he is from Outside of Incarceron. Most of Incarceron's inmates don't believe there is an Outside. It is during an ambush on the Civicry that Finn plays captive to get them to stop. As they are trying to help Finn, a woman notices the mark of an eagle on Finn's wrist and says she has seen that mark before. Finn's interst is peaked and he takes the woman hostage to find out what more she knows. She has seen the same mark on a crystal. Finn takes possession of the crystal when it is offered as part of her ransom. He soon realizes it is a key. Finn, his oathbrother Keiro, Gildas a Sapient and a slave girl escape from their winglord in attempt to locate a door that Gildas has seen before that he thinks the key will unlock.