As Christmas arrives in the Bunker, the Time Team is inspired by a visit from their future selves to find a way to try to save Rufus. But when the Mothership jumps to 1848 California, they're forced to put those plans on hold and chase Rittenhouse back to the Gold Rush, where they encounter one of the era's most dangerous villains. Then chasing the Mothership to Korea in the winter of 1950, our team helps a stranded, pregnant refugee attempt to escape a tragic fate. Stuck with no way out, our team faces its toughest challenge yet, and in the process, come to terms with their feelings for each other.