Brother Day embarks on a journey that no other Cleon has ever attempted. Salvor prepares to make the ultimate sacrifice to return home.

On Terminus, Salvor witnesses how powerful the null field has become. Brother Dawn makes a daring choice.

Enjoiner Rue confides in Dusk about her distrust of Demerzel. Hober Mallow pulls a daring move. Day sets course for Terminus and the Foundation.

Dusk and Enjoiner Rue learn Demerzel's origin and true purpose. Tellem's plans for Gaal take a dark turn. On Terminus, Day confronts Dr. Seldon.