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.

In the season finale, 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.