So, the mystery man’s name isn’t really Weng-Chiang. And when he tells the Doctor his real name, well, the Doctor knows who he is.
It does not go better for the bad guy from there.
Yes, it seems like everything that can go wrong for Weng-Chiang, the more it actually does. He and his goons manage to capture Leela and try to force the Doctor to hand over the key to the bad guy’s “time cabinet”.
The Doctor doesn’t bat an eyelash and makes all the conditions: release Leela, release Jago and Litefoot, go on ahead and the Doctor will follow.
The man who isn’t really Weng-Chaing bows to all these, though that silent Mr. Sin may not like it very much.
What else goes wrong? The Doctor gets his name as Magnus Greel, to which the Doctor informs Greel that not only did he–a 51st century dictator–not win the war (the Doctor fought for the good guys, of course), but the Doctor tells Greel that Greel’s own time travel experiments didn’t work and are very dangerous.
Greel doesn’t believe that, but you’d think he wouldn’t have to by just looking in the mirror.
The one thing that goes his way is Mr. Sin manages to knock out the Doctor with a laser canon hidden in a golden dragon. Greel gets his key, and now just needs his current victims in the basement.
But the Doctor rescues them as well as Litefoot and Jago with help from some improvised explosives that take out more of Greel’s minions.
And Leela managed to sneak around and almost stab Greel.
And then Sin goes nuts with the laser and takes out most of the rest of the goons, but somehow can’t hit the Doctor or his allies.
Oh, and then Sin turns on Greel, Greel dies in his own life draining gizmo.and Sin is stopped when the Doctor rips some wires out of him. Problem solved.
Of course, Litefoot can’t quite explain tea to Leela, and Jago thinks the TARDIS is standard-issue for Scotland Yard, but that’s it for this rather racist serial.