|Edition: || US (VHS)|
|When: ||May 1994|
|Format: ||1 x VHS NTSC|
With the Doctor behaving rather oddly after his regeneration, the Brigadier finds the research center under attack after a robot steals the plans for the new disintegrator gun. Could the members of the mysterious Think Tank be responsible for the giant invader? How sinister are the intentions of the shadowy Scientific Reform Society? More importantly, can the Doctor recover in time to save the Earth from Atomic War?
Originally transmitted December 28, 1974 - January 18, 1975, this four part adventure heralds the beginning of the Tom Baker era for Doctor Who.