Martha unwittingly unleashes a fatal gunfight resulting in severe damage. In the alternate world, Catherine and Sam arrive at their destination, but encounter some unforeseen events. Bill then tries to contact Catherine, but when he can't reach her, he turns to a drastic solution.

Bill investigates more of Catherine's findings and thwarts the aliens' deadly plans, but the group finds themselves in danger once again. Meanwhile, a run-in with the aliens ends tragically. Catherine secretly hatches a plan against her captors, but will she abandon Sam?

Catherine shares vital information about the black hole with Richard. Martha discovers Adina's destructive plan which the resistance group confronts. With little time left, the group is forced to take ever greater risks and make painful sacrifices to save the world.

Helpless against Adina's plan, Bill has no choice but to make a risky bet while his comrades prepare for a brutal end. In space, Richard and Juliet realize how close humanity is to annihilation, but will they be able to go to any lengths to save Earth?