Season three picks up as the war between the survivors and aliens reaches a new turning point and a terrifying phenomenon grips countless people across the globe. With stakes at an all-time high, one survivor sets out to investigate, forming a tentative partnership with another unlikely hero along the way. The pair will need to use every resource they have available to face an opposition more dangerous than ever in their fight, once again, for the survival of all humanity.

After an alien attack all but wiped-out mankind, the few survivors were in turmoil after a series of brutal losses. Having discovered a strange personal connection to the aliens, Emily is left to navigate a devastating possibility: could the invaders be human? Whilst the group get to grips with their new understanding of the aliens, the sheer desperation to survive drives many to extremes. And some will even contemplate sacrificing one of their own.