After receiving a strange message alerting them to danger, Steed researches some old files while Purdey and Gambit investigate. A legendary agent has resurfaced after 17 years. Working in a German circus as an acrobat, he discovered the identity of a double agent known as White Rat and shot him in the leg. He then lost his memory, but now remembers who he is and tries to contact his spy masters. The race is on to find him before White Rat does.