Lexell Kotov was an Archmagos Explorator, one of that restless breed of Tech-Priest driven to sail beyond the Imperium's charted stars in search of lost knowledge and forgotten worlds. Yet by the time of his great venture he was a diminished figure, for a succession of his forge worlds had been lost to him, and with them the prestige and the resources that had once made his name. Facing censure and decline, Kotov gambled his remaining strength on a single throw: an expedition to reverse his fortunes or perish in the attempt.
His prize was the Speranza, an Ark Mechanicus of staggering antiquity, a vessel so vast it served as a mobile forge world in its own right. Raised from the deep vaults of one of Kotov's own worlds where it had lain dormant and half-understood, the Speranza carried within its hull knowledge from the Dark Age of Technology and weaponry that bent time and gravity to its purpose. Around this leviathan Kotov mustered his crusade and set course for the Halo Scar, a lethal astronomical barrier at the fringe of the galaxy, beyond which lay the object of his obsession.
That object was the lost expedition of Archmagos Vettius Telok, and the fabled device Telok had sought, the Breath of the Gods, an archeotech relic said to hold power over the very life and death of stars. To chart the passage Kotov gathered a company of the brilliant and the strange, among them the stellar cartographers Vitali and Linya Tychon, a rogue trader of the Surcouf line, and a troubling machine-intelligence that named itself Galatea. Together they braved a crossing that claimed many of their number.
When at last the survivors reached the world where Telok held court, Kotov found not a fellow seeker but a madman. Telok had been consumed by ambition and delusion, and meant to turn the Breath of the Gods against the Imperium itself, to snuff out the stars of Terra and Mars and rule over the ashes as a new master of mankind. In confronting that ruin Kotov's crusade became something greater than one archmagos's bid for redemption; it became a struggle over a weapon that could unmake worlds, and a grim testament to the peril that waits for those who chase the deepest secrets of the ancients.