On the outskirts of Charleston, the Mason clan and the remaining 2nd Mass suddenly find themselves under brutal attack by a new Espheni war machine - and a new deadly creation that is unlike anything they've previously encountered.

The Espheni reveal their new plan to Tom, and he is faced with an impossible decision. Elsewhere, Anne leads an exhausting search for her daughter Lexi, while Ben's concerns about Lexi's increasing powers uncovers a devastating secret she's been keeping.

Tom and the 2nd Mass hatch an elaborate plan to escape the confines of the Espheni Ghetto. Meanwhile back in Chinatown, Maggie confronts Lexi publicly about keeping a deadly secret. At the Espheni Youth Camp, Matt tries to talk Mira out of a dangerous escape plan.

After breaking out of the Espheni Ghetto, Tom and the 2nd Mass seek refuge in a Volm hideout, where tensions run high between the Volm and humans. In Chinatown, Anne is reunited with Lexi, and realises that the little girl she saw six months ago is now a grown woman.

After freeing Matt from the youth camp, Tom encounters two strangers in the woods, who attack his family before embarking with him on a violent journey. Hal faces almost insurmountable odds as he tries to lead the remaining Volm and 2nd Mass to a place of safety.

After months apart, Tom finally reunites with his family and the 2nd Mass but the joyous reunion is cut short as Lexi undergoes a health crisis tied to her hybrid DNA. The crisis pits family members against one another while Anne goes to great lengths to save her.

Lexi emerges more powerful and ruthless than ever. Tom and the 2nd Mass must work together with the Volm to hold off the invading Espheni forces in what becomes the bloodiest battle of the series.

The 2nd Mass picks up the pieces after an alien attack leaves Maggie fighting for her life... and Hal fighting for Maggie. Tom and Dingaan Botha are cut off from the rest of the group, buried under tons of rubble, where they must rely on an Enemy Ship to rescue them.

Attempting to dig out a shot-down Beamer, Tom and a small team follow the Volm to a supply cache in search of equipment to expedite the process. Back at camp, Ben teaches Maggie to hone her new skills, while Pope and Sara have a fight from which they may never recover.

Tom and the remnants of the 2nd Mass learn to pilot a Beamer as part of their plan to destroy the Espheni Power Core, and the group draws straws to see who will embark on the dangerous mission.

Tom's mission to destroy the Espheni Power Core is complicated by Lexi's return. Lexi has to take extreme measures to save her father's life - and her own - after a Beamer malfunction. Meanwhile, the 2nd Mass fears an impending Espheni strike by the scorched Overlord.

With the weight of humanity's survival on Tom and Lexi's shoulders, they must defeat Tom's mortal enemy and destroy the Espheni Power Core. Meanwhile, an Espheni bomb is dropped onto Chinatown - immobilising the 2nd Mass and preparing them for Human Skitterizaton.