William Andersson was a young kid when a horde of aliens called the Asserai attacked earth, destroying his home and family with it. After years of serving humanity he finally gets a chance to redeem his family as he is drafted into a special operations program called 'Phoenix' and granted an expirimental suit of armour. Along with his 6 new comrades he is send out on missions to weaken the Assari so that humanity might win the war. Though it seems that problems arise as William uncovers the dark past of one of his squad members