Live And Learn/The Armory The world is left in tatters after a sudden, unprovoked and unexplained invasion by aliens, leaving the planet's remaining human population to fight for survival against the occupiers. History professor Tom Mason has been named second in command for the 2nd Mass, but his real focus is on his three sons, one of whom has been captured by the aliens for an unknown purpose. While scouting for supplies, Tom, Hal and their squad encounter a gang of marauders determined to get their hands on the 2nd Massachusetts' weapons. Leading the gang is an ex-con named John Pope, who decides to use his hostages as bargaining material.
Prisoner Of War A doctor who shares a history with Tom arrives at camp, and he may hold the key to saving the kids who've been abducted by aliens. Meanwhile, the ragtag crew has nightmarish encounters with skitters and mechs.
Grace Tom and his crew undertake a mission to retrieve motorcycles and cautiously allow Pope to join them. While on the task, they're attacked by a harrowing entity that may be even more formidable than aliens. Elsewhere, Anne and Harris hit upon a crucial discovery.
Silent Kill Hal orchestrates a shadowy and perilous plan to slip into an alien lair to rescue Ben and other ensnared kids.
Sanctuary, Part 1 Another resistance leader appears at the camp, sounding an alert that the aliens will soon attack and offering to take the children to safe shelter. With time running out, Tom and the others must weigh his proposal.
Sanctuary, Part 2 Suspicions arise that danger may indeed lurk at the children's safe haven. Before long, Mike happens upon a harrowing truth and an unanticipated enemy emerges.
What Hides Beneath Weaver turns more and more erratic, stirring up trouble while on a reconnaissance mission with Tom and Hal. Meanwhile, Pope constructs a potent weapon; and Anne makes a startling discovery while performing an autopsy on a skitter cadaver.
Mutiny Growing tension divides the 2nd Massachusetts just as their ambitious assault on an alien base draws near. Meanwhile, Tom has trouble coming to grips with Annie's profound discovery and its implications.
Eight Hours The resistance fighters launch a bold attack against the aliens as Tom remains at the camp to protect the civilians. Twisting developments lead Tom to a close encounter of the harrowing kind, and mysteries about the aliens' motives might finally be answered.