Set 152 years after the events of season two, The Foundation has become increasingly established far beyond its humble beginnings while the Cleonic Dynasty's Empire has dwindled. As both of these galactic powers forge an uneasy alliance, a threat to the entire galaxy appears in the fearsome form of a warlord known as "The Mule," whose sights are set on ruling the universe by use of physical and military force as well as mind control. It's anyone's guess who will win, who will lose, who will live and who will die as Hari Seldon, Gaal Dornick, the Cleons and Demerzel play a potentially deadly game of intergalactic chess.

In Season 2, as the Cleons unravel, a vengeful queen plots to destroy Empire from within. Hari, Gaal and Salvor discover a colony of Mentalics with psionic abilities that threaten to alter psychohistory itself. The Foundation has entered its religious phase, promulgating the Church of Seldon throughout the Outer Reach and inciting the Second Crisis: war with Empire.