Preparing to expose the mole at MI5, Ena's husband Henry is abducted by Special Branch and Ena is thrown into a murder case. All the evidence points to Henry having killed the mole, leading Ena to conclude that Henry is being framed. Close to finding out the truth, Ena is suspended from her job at the Home Office and the investigation is blocked by Special Branch. Only her sisters and her old friend Inspector Powell believe Henry is innocent. Help comes from an untrustworthy character. A deal is agreed: A ticket to Austria in return for the names of the mole's associates, evidence to solve two of Ena's cold cases, and the proof that Henry is innocent of murder. The catch? Ena must accompany this character to Austria as insurance.