The dude on the right is Mawdryn, played by David Collings, a character actor that everybody loves and who we saw a few months ago in “The Robots of Death”. He and his seven fellow mutants are not wearing the most fashionable in outer space wear. Marie called their clothes “terrible bridesmaid dresses.” Even when you’re missing a chunk of your scalp, it’s hard to look menacing dressed like that.
But Mawdryn isn’t a traditional villain. He and his gang stole some Time Lord tech several centuries ago and have been trapped in perpetual, mutating rejuvenation ever since. All they want now is to die, and by chance, the Doctor has shown up. Apparently he can exchange the potential energy from each of his remaining eight regenerations to kill all eight of the gang, but he’ll never be able to regenerate again himself. As motivations go, I think that’s incredibly original. It’s also a little convenient, what with the numbers working together like they do, but that’s fiction for you.
I’m glad to say our son came around in the end. As I remembered, there’s a good bit of padding in part four, reminding everybody of the plot, emphasizing all the relevant points again and again, but there are enough moral dilemmas and runarounds to keep things moving, and our son was very happy with the adventure. It even ends with an explosion! It may not be a great story, but it made a splendid recovery from that lousy opening installment.