The sinking of a commercial boat, followed quickly by the death of an underwater cameraman, gets SHADO’s attention focused on the Atlantic Ocean. Reports of objects resembling metallic flying fish tie both incidents together, and Straker orders Skydiver to investigate the region near a volcanic island where the boat was attacked. Skydiver’s sensors find an underwater power cable connected to a large artificial dome structure. When Straker and Foster investigate that dome in person, they see one of their own inside – a possible traitor within SHADO’s midst. They return to SHADO HQ, only to find the presumed traitor there too, but when questioned, he remembers nothing about the underwater dome. Straker and Foster return to the dome, this time to go inside and investigate…and what they find is their entire crew, and the SHADO control center, duplicated in every detail by the aliens…and ready to take over the real SHADO HQ.
Cast: Edward Bishop (Cmdr. Straker), Michael Billington (Col. Foster), James Cosmo (Lt. Anderson), Gordon Sterne (Helmsman), Conrad Phillips (Skipper), Fredric Abbott (1st Seaman), Richard Caldicot (Film Producer), Mark Griffith (Underwater Cameraman), Keith Bell (Film Director), Gerald Cross (Insurance Man), David Warbeck (Skydiver Captain), Anouska Hempel (Skydiver Operative), Wanda Ventham (Col. Virginia Lake), Barry Stokes (Skydiver Navigator), Ayshea (SHADO Operative), Vladek Sheybal (Dr. Jackson), Dolores Mantez (Moonbase Commander), Steven Berkoff (Astronaut)
LogBook entry by Earl Green