This is Ky with Jo Grant and Sondergaard and Cotton:
At the end of the story he defeats the baddys with his fabulous powers.
At least I think that is what happens. I didn't understand all of it.
I like the monsters in the story, they are googly-eyed aliens called Mutts and it turns out they are not baddys really. It is a fun story and one of my favourites with Jon Pertwee in.