Charlie Isaacs and his family arrive in Los Alamos and attempt to navigate a community built on secrets. Frank Winter, the head of the Manhattan Project, struggles with the sacrifices he is making to help the U.S. win World War II.

The community reels after losing a member, while new security measures affect the scientists' work.

The arrival of a high-profile guest shakes things up; Frank is haunted by his past.

When Babbit's past comes back to haunt him, Frank clashes with Charlie to protect his mentor.

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

Helen and Charlie must solve a crisis at the reactor. Frank and Liza help Paloma's family. Abby begins a journey of self-discovery.

Charlie and Frank both face serious questions about the future of their projects.

Charlie and Frank are forced to work together for the good of the project. When they run into a problem, Frank turns to an unconventional resource.

Wives explore their inner desires. Visit from dead "spy's" spouse. Winter explores an unusual solution to ignition problem.

A development overseas re-invigorates the hunt for a spy on The Hill. Charlie and Abby make a sacrifice when the plan with Frank is threatened.

Akley becomes vulnerable when he tries to fix Thin Man's shortcomings.

Frank is given a life-changing opportunity, while Charlie finds himself in the US Army's hotseat.