A Darkness at Sethanon recap

Murmandamus brings the Northlands south, and the Kingdom cannot tell what he is really after. Arutha rides north in person with Jimmy, Locklear and Baru and reaches Armengar, a fortress-city of Kingdom exiles commanded by the disgraced Guy du Bas-Tyra. Armengar is besieged and falls; Guy destroys it to cover his people's escape south, and Murmandamus turns toward the eastern city of Sethanon. Meanwhile Pug and Tomas find Macros alive, and with his help travel back to the Chaos Wars to watch the Valheru rise against the gods and forge the Lifestone, the artefact buried beneath Sethanon, and to learn of the devouring force from beyond the universe that the Dragon Lords fled. The Kingdom's armies converge on Sethanon and the battle turns into a siege of a city already burning. Below it Arutha kills Murmandamus and discovers he was a Pantathian serpent priest in disguise. The Lifestone wakes and the Valheru return; Tomas, Pug and Macros drive them back, and the stone is sealed and left dormant with a guardian set over it.

Previously, in the Riftwar Saga: an invasion from the world of Kelewan began a nine-year war on Midkemia. Pug, an orphan of Crydee enslaved on the invaders' world, was trained by their Assembly of Magicians and became the Kingdom's greatest magician; he now runs an academy at Stardock. His friend Tomas took the ancient armour of a Valheru, a Dragon Lord of the age before men, and now rules the elven forest of Elvandar with Queen Aglaranna. The war ended when the sorcerer Macros closed the rift, apparently dying; Lyam conDoin was crowned King, his brother Arutha became Prince of Krondor, and their half-brother Martin was made Duke of Crydee. In Silverthorn, a guild of assassins hunted Arutha and a poisoned bolt meant for him struck his wife Anita instead. Arutha faked his own death and rode north with Martin, Jimmy, Laurie, Roald and the Hadati hillman Baru to fetch the only cure, which grew in moredhel country. They got it and Anita recovered, but the campaign revealed the real enemy: Murmandamus, a moredhel leader who has united the Northlands, wants Arutha dead in particular, and is aiming at something buried beneath the eastern city of Sethanon that neither Pug nor the priests of Ishap can identify.

A year on, the Kingdom is preparing for a war it cannot yet describe. Murmandamus's host is growing in the Northlands and the northern garrisons report movements they have no numbers to oppose, but the Kingdom's lords are slow to believe that dark elves are anything worse than a bad raiding season. Arutha, who has already been the target of two campaigns of assassination, is not prepared to wait for reports and decides to see the north himself. At Stardock, Pug reaches the conclusion that has been forming since Sarth: the moredhel are being used. Whatever is directing them is neither moredhel nor human, it is patient enough to have worked for centuries, and the only person who ever seemed to understand the pattern was Macros, who is supposed to be dead. Pug and Tomas set out to establish whether he actually is, because the alternative is to face what is coming without knowing what is under Sethanon.

Arutha travels north with a small party, Jimmy, Locklear and Baru among them, moving quietly through Yabon and into country the Kingdom has no maps for, and finds the reports were understated: the moredhel are not gathering, they have gathered, and the host is already moving. Pug and Tomas go first to Elvandar and then to Macros's island, where they pick up the trail of a man who left instructions rather than a body, and the golden dragon Ryath carries them onward. The two journeys are the book's two halves: one party is trying to measure an invasion in the field, the other to find out what the invasion is actually for. Neither yet suspects how far back the answer goes.

Arutha's party is driven north rather than south and reaches Armengar, a fortified city of humans in the far north that the Kingdom knows nothing about, built by the descendants of people pushed out of the Northlands generations ago. It is commanded by Guy du Bas-Tyra, condemned and exiled after the Riftwar, with Amos Trask beside him, and it is the one thing standing between Murmandamus and the passes south. Murmandamus brings his whole host against it. Arutha, who came north to count the enemy, finds himself inside a siege alongside the man he most despises, and has to work with him. Meanwhile Pug and Tomas find Macros alive, held where he could not free himself, and learn that his survival was neither an accident nor entirely his own doing.

Armengar cannot be held. Guy fights the siege to the last possible hour and then destroys the city outright, firing its stores to cover the escape of his people south through the mountains, and the survivors make it to Kingdom territory with the enemy behind them. Murmandamus turns his host toward Sethanon, and the Kingdom finally understands where the invasion has been aimed all along. Pug, Tomas and Macros go a different way for their answers: back in time to the Chaos Wars, where they watch the Valheru rise against the gods, see Ashen-Shugar and Draken-Korin at the end of their age, and witness the forging of the Lifestone, the thing that lies buried beneath Sethanon. They also learn what the Valheru themselves were fleeing, a devouring force from beyond the universe, and why waking the Lifestone would be a catastrophe far larger than the loss of a kingdom.

Every force the Kingdom can raise converges on Sethanon: Lyam's eastern armies, Martin's western levies, the Tsurani settled at LaMut, Dolgan's dwarves and the elves of Elvandar. Murmandamus reaches the city first and the battle becomes a fight through a burning town rather than a siege of it, with the defenders selling ground they cannot hold to buy the relief columns time. Arutha, Jimmy and Locklear go under the city, following Murmandamus down toward the chamber where the Lifestone lies, because whatever the armies do above ground the question will be settled below it. Pug and Tomas race back from the past to reach the same chamber. Not everyone who set out from Krondor is still alive to see it.

Beneath Sethanon, Arutha kills Murmandamus and finds that the moredhel messiah was never moredhel at all but a Pantathian serpent priest working behind an illusion, one of a race that has spent centuries steering the Northlands toward this one objective. The Lifestone, made by the Valheru in the Chaos Wars as their way back into a world the gods had taken from them, begins to wake, and the Dragon Lords come for it. Tomas, drawing on everything Ashen-Shugar left in him, and Pug, with Macros restored to the fight, hold them and turn the host away. The stone is not destroyed; it is sealed and left dormant where it lies, with the Oracle of Aal set beneath the city to guard it, a danger postponed rather than removed. Macros survives greatly diminished and goes his own way. Above ground the invasion collapses with its leader, and King Lyam pardons Guy du Bas-Tyra and resettles the survivors of Armengar. The Kingdom is at peace, and only a handful of people know what was actually decided under Sethanon.

The invasion is broken at Sethanon. Beneath the ruined city Arutha kills Murmandamus and finds that the moredhel messiah was never a moredhel at all but a Pantathian serpent priest working behind an illusion, one of a race that has spent centuries manipulating the Northlands toward this single objective. What lies under Sethanon is the Lifestone, made in the Chaos Wars by the Valheru as their means of returning to a world the gods had taken from them. Its waking calls the Dragon Lords back, and they come. Tomas, drawing on everything Ashen-Shugar left in him, and Pug, with Macros restored to the fight, hold them off, and the host is turned away. The Lifestone is not destroyed. It is left sealed and dormant where it lies, with the Oracle of Aal established beneath the city to guard it, a problem deferred rather than solved and one that Pug expects to have to answer for eventually. Macros survives, greatly diminished, and goes his own way. Guy du Bas-Tyra is pardoned by King Lyam and the survivors of Armengar are resettled in the Kingdom. Arutha returns to Krondor with Jimmy and Locklear. The Kingdom is at peace again, the north is broken for a generation, and the people who understand what happened under Sethanon are a very short list.