A Darkness at Sethanon is the third and final book in The Riftwar Saga. It describes how Murmandamus, a new prince of the Dark Brotherhood, marshals the forces of the Moredhel and invades the kingdom, with the intent of finding the Lifestone, a powerful relic with which he will be able to destroy every living thing in the world, so as to resurrect the Valheru Lords of old. Only Pug and Tomas can stop this new evil, thereby ending the Riftwar.