Emperor Frederick IV of House Corrino is desperate for the harvesting of the valuable drug melange (also known as 'the spice'), only found on the planet Arrakis, to pay off all of his debt incurred on internecine wars with family members. To achieve this, he now offers the sole governorship of Arrakis to the House (Atreides, Harkonnen, and Ordos) which delivers the most spice for him. War begins as deputations from all three Houses arrive on Arrakis.
Even more Harkonnen forces rush into Atreides defences, including the mighty Devastator tank. The Atreides deploy Siege Tanks and Rocket Turrets to counter this threat.