Desiree Ross

The Mason clan and the remaining second Mass are attacked by a new Espheni war machine. The Masons must forge new relationships and abilities to survive.

Tom and the 2nd Mass hatch an elaborate plan to escape the confines of the Espheni Ghetto. Meanwhile back in Chinatown, after learning from Ben that Lexi has been keeping a deadly secret, Maggie confronts Lexi publicly. At the Espheni Youth Camp, Matt tries to talk Mira out of a dangerous escape plan. While trekking through the woods with her guerilla fighters, Anne has a flashback to her time in the Espheni Tower with Karen, where a terrifying secret about Lexi is revealed.

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. Tom sets off with Weaver and Cochise to find Matt, leaving Hal in charge. Meanwhile in Chinatown, Anne is reunited with Lexi, and comes to realize that the little girl she saw 6 months ago is now a grown woman.

With the weight of humanity's survival on Tom and Lexi's shoulders, they must defeat Tom's mortal enemy and find a way to destroy the omnipotent Espheni Power Core. Meanwhile, a new, terrifying Espheni Bomb is dropped onto Chinatown – immobilizing the 2nd Mass and preparing them for Human Skitterizaton – in the season finale episode.

While members of the 2nd Mass attempt 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. Along the way, they encounter a friend – and must decide whether or not to trust her. Back at camp, Maggie and Ben grow closer as he teaches her to hone her new skills, while Pope and Sara continue to clash, resulting in a fight from which they may never recover.