Chicago, 1950. Rosalind Porter has always defied expectations - in her work as a physicist on the Manhattan Project to design the atomic bomb, and in her passionate love affair with coworker Thomas Wheeler. Five years after the end of both, her guilt over the results of her work and her heartbreak over Wheeler are intertwined. She has almost succeeded in resigning herself to a more conventional life. Then Wheeler gets back in touch - but so does the FBI. Agent Charlie Szydlo wants Rosalind to spy on Wheeler, whom the FBI suspects of selling nuclear secrets to Russia. Rosalind final assignment launches her on a mission to find the truth . . . no matter where it leads.