The BEST episodes written by Ian Scott Stewart

#1 - Flight Path

UFO - Season 1 - Episode 15

A SHADO technician, being blackmailed for information by an unknown party, is caught by Freeman, but not before the information is passed. The technician divulges to SHADO the information he gave to the blackmailers and, after much work on the encrypted data, they discover it is part of a plan by the aliens to attack the Moonbase undetected.