American astronauts and NASA leadership prepare for a new mission with unlikely partners. Ellen gets in touch with an old friend.

Ellen is challenged by her new role. Margo’s allegiances are put to the test. Karen explores new opportunities—personally and professionally.

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

Nearly 10 years have passed. Danielle and Ed attend a celebration, where things take a terrifying turn.