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 Weaver. Five years after the end of both, her guilt over the results of her work and her heartbreak over Weaver are intertwined. She has almost succeeded in resigning herself to a more conventional life. Then Weaver gets back in touch – but so does the FBI. Agent Charlie Szydlo wants Rosalind to spy on Weaver, whom the FBI suspects of selling nuclear secrets to Russia. Rosalind’s final assignment launches her on a mission to find the truth – no matter where it leads.