Tom's life hangs in the balance as his beamer drifts into space during which he encounters a surprising guest. Meanwhile, the 2nd Massachusetts go on the offensive against the espheni

A surprise skitter attack leaves the 2nd Mass without food. In desperation, Maggie, Ben, Pope, and Sara go on a dangerous mission hoping to find supplies. Along the way, they encounter a family deeply scarred by the Espheni plan. Maggie must make false promises to insure the 2nd Masses' survival.

The 2nd Mass discovers the source for the seemingly endless supply of enemy forces. With the Volm's help, Tom's leadership begins to spread to remaining human militias around the world. Hal disobeys his father to help Maggie on a personal mission. Meanwhile, Tom has to make an agonizing choice that ultimately risks one of their own, leaving lasting repercussions for them all.

A mission to procure vehicles and fuel goes awry. Cochise shares troubling news with Anne that will test both her medical and leadership skills. Anthony's mental stability and his loyalties are brought into question. Meanwhile, a desperate Pope takes things into his own hands.

The 2nd Mass leaves Chinatown en route to what they hope will be the final Espheni battle. Along the way, they encounter a deranged and desperate gunman who takes Weaver hostage. Meanwhile, Tom sets off to rescue Hal from Pope and his dangerous group of survivors.

Injured, Tom takes refuge with a unique family who has distanced themselves from the fight, giving him a glimpse of life without war. Hal and Isabella's romance grows as they search for a missing Tom. Meanwhile, The 2nd Mass locates an Espheni device that could be a linchpin to winning the war if they can figure out how to use it. And Maggie makes a decision that has consequences for her and the entire 2nd Mass.

The 2nd Mass arrives at a safe haven - a functional military base run by Weaver's old colleague and flame, Captain Katie Marshall. As the two groups make plans for the final assault on the Espheni, the 2nd Mass begins to realize that things aren't exactly as they seem.

Weaver discovers a shocking truth about an old friend and must decide how to best protect the 2nd Mass. Maggie and Isabella are forced to work together, while the remainder of the 2nd Mass attempts an escape led by Tom.

Tom gains a powerful new weapon against the Espheni. Ben puts his life on the line to extract enemy plans. Pope discovers that Tom is alive, and launches a final attack. Meanwhile, the 2nd Mass must reassess their situation when an unexpected visitor appears.

The final standoff brings the Masons, the 2nd Mass, and their new allies into the bowels of an iconic American location, wrought with new and unpredictable obstacles. Despite great loss along the way, they must persevere with hopes of once and for all reclaiming Earth and humanity.