This is Tom Baker's first outing as the Time Lord and after a bit of sartorial juggling, we are introduced to the staple long coat, longer scarf and floppy hat. Suffering from a bit of regenerative jet-lag, he has to get to grips with a series of robberies from the most secure of government facilities. The "Brigadier" (Nicholas Courtney) has put him under the medical care of "Harry" (Ian Marter) so hopefully he and "Sarah Jane" (Elisabeth Sladen) can discover the dastardly culprits before a very dangerous weapon is constructed and a nuclear disaster is orchestrated by a malevolent gang of folks...