Gerry Anderson Classic ITC Entertainment & Century 21 TV Production Music from Stingray and Joe 90 can be heard in this episode
A build-up of UFOs have to be discovered by a Deep Probe 87, which lead Straker to be believe that the aliens are planning to bypass SHADO defence by using replicates of the SHADO personnel in a replicate SHADO control room in a dome construction under the Atlantic ocean.
