This time we swapped sides and I took the role of the traitors and Luke played the staunch loyalists. My first move after some successful corruption and bombardment was to drop pods some World Eaters into the southern hive and attack the Fabricator General and his men. I succeeded in driving all his men out, before being forced to retire in turn. In the battle that had erupted where men had turned to the forces of chaos I defeated the Imperials and found myself in control of all 4 spaceports earlier than planned, so now tried to reinforce as quickly as possible to hold onto them until I could claim victory.
Angragon and the forces of Khorne found themselves under a viscous counterattack from the Khan and his White Scars. Despite the loss of Angragon I managed to hold the spaceport, and eventually re-enforce it (Here I also used a nice little card combo, terrify with daemons to force three units of lesser rank to rout with blood for the blood god, to make routers be eliminated instead).
Meanwhile I had re-enforced two of the other spaceports with the forces of Tzeentch and Slaanesh. The eternity gate spaceport however was held by a small force, although it included Montarion and a Chaos Titan. An attempt to reinforce it with Death Guard Marines in Drop Pods met with utter failure as they were all destroyed by the mass of defence lasers around the port. The Imperial forces then launched their final counter attack. By the time this was over we would be virtually at the spaceport victory turn and if they had not dislodged the traitors all was lost. Rogal Dorn led Imperial army units, Blood Angels and his own Imperial Fists against the bridgehead. Using the combat card maleficent plague I forced Luke to use 5 shield to avoid the risk of having his whole force wiped out. This meant that his final play of card gave him 10 damage, I countered 3, leaving 7 to absorb, which I managed leaving just one battered Nurgle war-band to hold the port, and claim victory for the forces of Horus. Should Luke have taken the risk to ensure he had the combat power? We will now never know for Terra has fallen to the Chaos lords.