Doctor Who goes to the planet where the Cybermen are all sleeping underground for some reason. He meets a bunch of guys who want to wake the Cybermen up, so they can get killed by them.
Doctor Who is not sure this is a great idea, but he is also quite interested to see what it will look like, so he lets them do it.
The Cybermen all sleep in these exciting space bunks. They wake up.
It is a quite convincing depiction of people waking up after a big sleep, as they all stumble around for a bit, looking confused and horrified and like they don't even know who they are.
This guy with the massive head is the Cyber Controller.
He is the best Cyberman, even though he looks like the worst. The one at the front is thinking "How did this guy get to be controller? He never shows up for meetings and his head looks like a penis!"
Raar! This Cyberman is doing a pounce, like a metal leopard.
Pretty much everyone in the story gets killed by the Cybermen. Which makes the story quite effective - they're mostly quite interesting characters, so you're a bit sad when they all die horribly to satisfy Doctor Who's curiousity.