As the project falters, Charlie turns to an unlikely partner for help.
When a crucial dry run fails just weeks before the Trinity test, Charlie and Frank are forced to work together, setting aside old wounds for the good of the project. Unbeknownst to everyone, including Charlie, Frank made certain the test would fail to get him back into the project. Abby is forced to face truths about Charlie's past when Charlie's father contacts her. Crosley and Hogarth's spy story culminates when they depart the Hill with a cache of stolen documents, only to be captured and returned to Darrow, who has a surprise in store for Hogarth. Meeks receives new orders from Nora, along with a new understanding of his role in the mission. Liza continues studying the potential health effects of the test and receives surprising help from Fritz. Helen's romance with Stan, the patent lawyer, deepens, leading to a surprising new prospect for her future.
