UFO: Reflections in the Water (Episode 24)

Following the sinking of a freighter ship and the death of an underwater cameraman, Straker and Foster take the submarine 'Skydiver' to examine the ocean bed. They come across a vast domed building and, from a distance, think they see SHADO Lieutenant Anderson in the dome. Back at headquarters Straker interviews Anderson, who claims to know nothing of the dome. It is part of an alien plot to create doubles of the SHADO staff - including Straker - to by-pass SHADO security systems. The dome has to be destroyed with its occupants.