When an agent at the Ministry of Top-Secret Information is murdered, Steed and Tara have little difficulty in locating the man responsible. But when a handwriting test indicates that he is Boris Kartovski, someone Steed thought he had killed in Berlin 5 years before, our heroes find themselves drawn into the dangerous experiments of Dr. Constantine.
| Creator | Sydney Newman |
|---|---|
| Actor | Patrick Macnee, Linda Thorson, William Lucas |
| Country | United Kingdom |
| Production | Associated British Picture Corporation |