The Quake 4 single player mode continues the story of Quake II by pitting the player against a cyborg alien race known as the Strogg. The game follows the story of a Marine Corporal named Matthew Kane who is joining the elite Rhino Squad. Following the success of the protagonist of Quake II in destroying the Strogg's leader, the Makron, Rhino squad is tasked with spearheading the mission to finally secure the aliens' home planet Stroggos. In the course of the invasion, the squad ship is shot down and crashes in the middle of a battle zone, separating Kane from his companions. Kane eventually rejoins his scattered team members and partakes in the assault against the Strogg.