Love. Desire. Betrayal. Her choice could save a nation.

Chicago, 1950. Rosalind Porter has always defied expectations --- in her work as a physicist on the Manhattan Project, and in her passionate love affair with colleague Thomas Weaver. Five years after the end of both, her guilt over the bomb and her heartbreak over Weaver are intertwined. She has almost resigned herself to a conventional life.

Then Weaver gets back in touch --- and so does the FBI. Agent Charlie Szydlo wants Roz to spy on Weaver, whom the FBI suspects of passing nuclear secrets to Russia. Despite her better instincts, Roz has never stopped loving Weaver, but something about Charlie, a former prisoner of war haunted by his past, calls out to her. As Rosalind's feelings for each man deepen, so too does the danger in which she finds herself. She will have to choose: the man who taught her how to love, or the man her love might save?