Guilliman, Regent of Terra, led the Indomitus Crusade and left the Throneworld still in turmoil and plagued by cult activity. Huge armies have marched from the planet, following the primarch, and without them, the restoration of order hangs in the balance. The Custodians are doing everything possible to ensure the safety of the Palace, and the Sisters of Silence are reviving the citadel of Somnus on the Moon. When the Phalanx star fort returns to Terra, it seems that long-awaited stability is at hand, but as Imperial forces push deeper into the slums, they discover traces of a mysterious enemy. The truth is revealed - not all enemies are corrupted by Chaos, for many on the Throne Planet do not share Guilliman’s idea of a new order. The threat of civil war looms over Terra...