At the dawn of the 41-st millenium, there is only war.
You are part of a special Adeptus Astartes chapter Steelhawks, a group of Space Marines dedicated to preserving the imperium, and specifically given authority by the Custodians of Holy Terra.
Comprised of elite warriors from all over the Imperium, and all of the factions, this chapter operates in small teams, performing secret missions vital to the survival of the imperium.
Recently, you have been able to recover a stable sample of tyranid brain matter, sent to you by a conquered world. Ordered by the High Lords of Terra to transport it back to Mars for study, you now await your arrival aboard the Imperial Cruiser Seer, unaware of the danger that you and your battlebrothers will face...