Inside this 168-page hardback book, you'll find:

In-depth Lore and Background: Timelines, maps, and more covering the cataclysmic events on Mars during the Age of Darkness. From the Schism of Mars, the birth of the Mechanicum, and the key conflicts involved in the the Martian Civil War.

The Mars Campaign: The Onslaught Campaign System allows you to play linked battles of Warhammer: The Horus Heresy. Includes 10x core campaign stratagems, optional rules, and the Mars Civil War Campaign.

Core Missions: Provides 5x Core Missions: The Crucible of War; The Heart of Battle; Sudden Strike; Take and Hold; and Strike and Fade.

Apex Missions: Provides 3x Apex Missions which can be played as a linked set of campaign games using the Onslaught Campaign rules, or as one-off missions.

Dark Scions of the Questoris: Includes options for the Divisio Tactica: Questoris Household list found in Liber Mechancium.

Automata Malefica: Rules for using Corrupted Engines within a Traitor Mechanicum force.

Relic Hunt Missions: 5x Relic Hunt Missions: Data Coil Download; Unlock the Vault; Secure the Crash Site; Relic Extraction; and Convoy Raid.

Techno-heresies of the Dark Age: Rules for Proscribed Techno-arcana, accessible by some Traitor forces: Malefikite; Machin Malefica; Ruinous Cybernetica; Nekrotek; Ephemera Nekrotek; Malamina; Æthertek; and Anima Malefica.

Additional Unit Profiles: Includes 3x Legiones Astartes Army List profiles and 1x Mechancium Army List profile for the Krios Squadron.

Miniatures Showcase: A full-colour showcase featuring various Mechanicum miniatures.

In order to use the contents of this book, you will require the Warhammer: The Horus Heresy – The Age of Darkness Rulebook and one of the Army Books for Warhammer: The Horus Heresy, which are all available separately.