Two years after the Helghast assault on Vekta, the ISA is taking the fight to the enemy's home world of Helghan. The ISA goal is direct: capture the Helghast leader, Emperor Visari, and bring the Helghast war machine to a halt. Assuming the role of Sev, a battle-hardened veteran and a member of the special forces unit known as the Legion, players lead a group of highly trained soldiers on a mission to take out the Helghast threat. For Sev and his squad, the invasion of Helghan is just the beginning. Tasked with securing Pyrrhus, the Capital City, the team quickly discovers that the Helghast are a formidable enemy on their home planet. Not only have they adjusted to the planet's hostile conditions, they have also harnessed a source of power they can now use against the ISA. Sev discovers his squad isn't just fighting enemy forces their fiercest opponent may be the planet itself.