Frank and Charlie hatch a plan.

Frank clashes with Charlie to protect Babbit, who has become the subject of an investigation.

Frank seeks medical answers; Charlie and Helen travel to survey an off-site reactor.

Helen and Charlie deal with a crisis; Abby embarks on a journey of self-discovery.

A drama about the clandestine race to build the world’s first atomic bomb in Los Alamos, N.M., centers on a self-destructive professor who is commissioned to help lead the Manhattan…