The Avengers (1961)

S06E22 Stay Tuned

As Steed prepares for his vacation, he is suddenly knocked out cold. Upon regaining consciousness, he resumes packing, only to be perplexed when Tara shows up to inform him that he’s been missing for three weeks. Is there a connection between his disappearance and the enigmatic figure tailing him, a person that everyone else seems to notice except for Steed?