A secret agent is fighting with the opposite in an old glass factory. Then he has been shot by a kind of arrow with a drug which erases his memory temporaly. Unless he finds his way to Steed's appartment and tells Steed there is a traitor in the organisation. Steed doesn't know how to handle this case and goes to mother, his boss (a new personage who has played a several times in the Tara King episodes.) In this episode we say farewell to Emma Peel in an emotional way; her husband has just returned out of the Amazone and Tara King is introduced as the new partner of Steed. This episode forms in fact a bridge between two seasons.