Episode 4 (S01E04)

After GCHQ suffers a cyber attack, Jerry proposes that the hacker should be invited to join their team. However, Joseph feels envious of Jerry's exciting new companion and decides to revamp his persona in an effort to regain Jerry's attention. At the same time, reserved cryptanalyst Mary prepares to meet her former boyfriend for the first time in four decades, as he has been invited to give a seminar at GCHQ.