This is probably one of the more conventional Dr. Who stories. That doesn't make it any less fun. It stars Tom Baker as the Doctor, my favorite of the "classic" Doctors. He pops in on a very gothic planet where every night is dark and stormy. The Doctor is peeved cause he knows that this was caused by the other Time Lords and there is some mess he's expected to clean up. He does what any reasonable person does, he pouts.
Meanwhile, in the very gothic castle there is one mad scientist and one probably mad helper with a wicked hook for a hand. The Scientist is looking for the perfect head, the helper has yet to provide said perfect head which causes work relation stress. Meanwhile, in a very gothic cave a bunch of ol' gals are upset cause their eternal flame is going out. They then find out that there's a Time Lord in the wood shed and they fret that he wants the last of their serum of immortality.
So the Doctor wanders between these two camps. The Scientist believes the Doctor has the perfect head (of course!), and the sisterhood tries to burn him at the stake when their biddy mind tricks don't work. The Doctor takes this all in strides and tries the unlikely tactic of talking with people which works more than you think it would.
Oh, the brain? The brain is the last little bit of Morbius a renegade Time Lord and all around bad apple. The Scientist has already built a rather ro-manish type body and just needs the Doctor's head to complete the perfect body for Morbius. Morbius can be characterized as snitty, short tempered, and impatient. He wants a body NOW.
This is probably one of the cheesiest of the Doctor's adventures. I love the faux gothicness of it. It moves fast and Tom Baker is always fun to watch.