Doctor Who/Recap/S14/E02 The Hand of Fear

"I must be mad. I'm sick of being cold and wet and hypnotised left, right and centre. I'm sick of being shot at, savaged by bug eyed monsters, never knowing if I'm coming or going... or been... I want a bath, I want my hair washed, I just want to feel human again... and, boy, am I sick of that sonic screwdriver. I'm going to pack my goodies and I'm going home..."

—Sarah Jane Smith

Arriving back in modern-day England, the TARDIS lands in an actual quarry for a change. Sarah touches what seems to be a fossilized hand and is taken over by the spirit of Eldrad, a Kastrian criminal punished by disintegration, but whose hand has survived, and whose spirit lives on inside the ring on its finger. Sarah takes the ring and goes to a nearby nuclear research station where she uses the energy to recreate Eldrad's body.

Eldrad persuades the Doctor to take him home to Kastria, but when they arrive, there is only a dead planet and a mocking message from the last king of the Kastrians. Eldrad, furious, forces the Doctor to take him back to Earth so that he can rule there instead. The Doctor and Sarah trip Eldrad using the Doctor's scarf and the crystalline being falls into a crevasse and shatters.

Returning to the TARDIS, the Doctor is summoned to Gallifrey and, as he cannot take Sarah with him, he gives her a lift home to Croydon - only for her to realise as he departs that she doesn't recognise the street where he's left her. (It is later revealed that he accidentally left her in Aberdeen...)

Tropes

Bizarre Alien Biology: Inverted. Sarah Jane is able to shake off the effects of a poison gas, because it is designed to be deadly to silicon-based Kastrians.
BBC Quarry: Played with, as the TARDIS lands in... an actual quarry.
Disney Villain Death: Eldrad.
Distant Prologue
The Dulcinea Effect: The Doctor seems a lot more willing to help Eldrad when s/he looks like a sexy blue chick rather than a hulking rock dude. Sarah Jane is rightly skeptical of Eldrad the whole time. Meanwhile, Eldrad was actually exploiting this trope.
Evil Sounds Deep: Eldrad's Kastrian form.
Fatal Family Photo: Fatal "last conversation with the wife and kids", anyway. Averted when the Professor survives rather than being killed off.
Glowing Eyes of Doom: Eldrad.
Helping Hands
Hypnotic Eyes

Doctor: "Sarah, I want you to look into my eyes."
Sarah: "OH NO, NO THAT'S NOT F__" (falls into trance)

I Love Nuclear Power: Eldrad can use radiation to regenerate a body! That's a useful trick.
I Was Just Joking: But you gotta go home anyway, Sarah.
Large Ham: Eldrad, after returning to his true form, starts to devour the scenery.
Most Annoying Sound: The Professor does not like the sound of the nuclear plant's alarm.
Name's the Same: As a being from Warhammer 40,000.
Pound of Flesh Twist
Put on a Bus: Sarah Jane. Although the Long Bus Trip lasted nearly 30 years!
- She did come back in 1983 for "The Five Doctors."
Sequel Hook: The call from Gallifrey leads directly into the next episode.
Silicon-Based Life: The Kastrian race.
This Is Not a Drill
Throw It In: Sarah Jane, after being released from Eldrad's influence, says "ELDRAD MUST LIVE -- just kidding!" This was a prank by Sladen meant to "corpse" Tom Baker, but it seemed so in-character that the director kept it in.
Ultimate Defence of the Realm: The RAF try to destroy the nuclear power station and Eldrad with a nuke. It doesn't work.
Women Are Wiser: A villainous example. Both Eldrads are in fact evil, but the female version is much more thoughtful and calculating, while the male version is a blustering moron who gets himself killed by tripping over a scarf.
The X of Y