It's another evening for Doctor Who and Sarah in the TARDIS, which is now made entirely of wood for some reason. They have clearly just seen something very unsettling, in the corner of the room.
Doctor Who looks absolutely horrified, which is unusual for him. Usually, when a terrible thing happens, he just laughs excitedly and assumes that all the upsetting stuff will happen to someone else. This must be something quite serious, like an invitation to a children's party or some sick.
Sarah doesn't look quite as bothered, does she? She doesn't like what she's seeing either, but her reaction is not so much, "Oh no, a terrible evil has been made manifest," and more, "Why would anyone leave the house in such a ridiculous hat?"
Anyway. I think it's some kind of Bad Energy Monster, and it's broken into the TARDIS somehow. Which Doctor Who has always maintained is impossible, so this is embarrassing.
The Bad Energy Monster lives in this magic blue crystally mountain zone. Doctor Who has gone there to register a complaint or something. He's standing in an imperious manner, trying to suggest that he'd like to see the most important person available, and glare at them until they give him a full apology for breaking into his TARDIS, and maybe some vouchers.
This is a pretty cool looking place and looks like lots of fun to hang around in. Sarah is wondering if it might be rather more enjoyable here, away from the day to day festival of whimsy that is Doctor Who's current incarnation. It would certainly be quieter, and those mountains look unlikely to throw her into the path of a monster, shouting "Rescue yourself - the pubs are open."
For reasons that I honestly can't remember, they go to Renaissance Italy for a bit.
This is a delightful image, isn't it? Sarah has many good qualities - the patience to deal with Doctor Who's emotional tantrums for example - but probably my favourite is the way she just gets into the local culture. Most of Doctor Who's companions in the past just wander around places shouting things like, "Why are you people all so primitive?" and "When can we leave so I can stop crying?"
Sarah's having a lovely time and has found herself some oranges to chat to. An orange might not be much to you and me, but to Sarah it's just nice to find someone - even an inanimate object - who will let her talk for two seconds without starting to burble on about how much cleverer it is than Winston Churchill.
Soon these guys turn up to ruin everyone's fun. They have been possessed by the "Mandragora" from the story's title, and now they're mad keen on chanting, and the sacrificing of maidens.
Actually, I'm pretty sure they must have been into all that before Mandragora came along. They already had the robes and terrifying masks ready to go. There isn't a big pause in the story, after the alien intelligence turns up, where they go off to fashion masks and measure each other's inside legs. They just instantly dress up like evil mad nightmare guys and prance about in their already-established Cathedral of Death. If I was Mandragora, I might start to feel a bit used.
The mask on the right is loads better than the one on the left, isn't it? It looks really proud, and evil, and full of unknowable cosmic rage. The other guy's mask just looks like he's at a wedding trying to bluff his way through "All Things Bright and Beautiful".
Doctor Who, meanwhile, has launched himself at the local evildoers. He is delighted to find that the main bad guy has the greatest beard in the history of beards. Look at him, not even trying to conceal the fun time he is having, laughing with joy and saying things like "Enormous!" We should congratulate Doctor Who, though, for managing to keep his hands in his pockets and not just running them through the beard while giggling.
Main Bad Guy has been trying to thrill and amaze Doctor Who with details of his terrifying plans to dominate the world. Needless to say not one word of it has made the slightest impact, and he is now looking around for somewhere to have a good cry.
As is often the case at this point in the story, Sarah gets captured by the "We love sacrifice" guys, and strapped to a rock.
Sarah is a long way past being frightened by this kind of thing. It happens pretty much every week and she has now built it into her routine. as a way to catch up on sleep. She knows that soon she'll be rescued by one of the following:
a) Whatever god these people worship - usually some kind of mad robot that doesn't even know it's being worshipped - will turn up to see what all the noise is about and murder all the bad guys with lasers.
b) The local resistance will have heard that there's a new pretty girl visiting the region, and will swoop in to help, in the hope that maybe she'll be their girlfriend or their mum.
c) Sometimes Doctor Who will accidentally stumble in, usually while trying to steal something, and Sarah can escape while everyone is trying to cope with the sudden arrival of an incredibly loud man who is making deeply hurtful personal comments about everyone he sees.
Eventually the evil worship guys do a big ritual, and that means that Mandragora can come into this dimension, or something along those lines. They are briefly delighted with the success of the ritual, but then they take off their masks to find that their faces have turned into nothing, so the victory is short lived.
Doctor Who wins by... um... I think he ties a big bit of wire to something, and that seems to blow everything up. It's another of those adventures that Doctor Who rarely discusses, and if anyone did he'd probably just say, "Masque of Mandragora? More like MASKS of Mandragora. Am I right? Eh? Hah!" before laughing himself to the point where he might actually genuinely be sick on himself.