The rivalry between American astronauts and Soviet cosmonauts intensifies as last-minute changes impact the Pathfinder mission plan.

Tensions between the U.S. and the Soviet Union reach an all-time high on the moon, throwing multiple missions into jeopardy. Season finale.

While Jill, Deirdre and Seb debate over who is to blame for Jeff’s recent behavior, Jeff finds himself in the real-world version of Pickle Barrel Falls.

The origins of Alpha and Beta are revealed; Alpha attempts to toughen up Lydia as they prepare to walk with the dead; the Whisperers create their herds.