Mortally weakened by the Spider Queen on Metebelis 3, the Doctor is forced to regenerate. His recuperation is cut short as UNIT investigate a spate of robberies involving components for a top-secret disintegrator gun. The culprit is quickly identified as a highly sophisticated robot built by Professor Kettlewell, which is being ordered to act against its Prim Directive. Just how is the robot being used to carry out the sinister agenda of the Scientific Reform Society? And can the Doctor rescue Sara from the robots clutches and avert a nuclear war?
With the newly-regenerated Doctor (Tom Baker) behaving erratically, Brigadier Lethbridge-Stewart and UNIT have to contend with the theft of the plans for the new disintegrator gun by what seems to be a mechanical monster. However, the theft is only the beginning of a plot to hold the world to nuclear ransom.n
This is a Region 4 disc, the local region for Australia.