Part four of The Keys of Marinus starts with Ian and Barbara still in the cold place they appeared in at the end of part three. There is snow and wind and haunting music like they're in the film Excalibur.
Ian and Barbara decide to have sleeps in the snow, which is quite surprising when they're supposed to be on an adventure, but then I quite often feel like having sleeps when I am supposed to be doing other things so maybe they were just sleepy.
A manny called Vasor finds them and takes them to his house where it is warm because he has a fire. When he wakes up Ian swaps his teleport bracelet with Vasor for some warm clothes and he goes to look for Altos, Susan and Sabetha.
Ian sees wolves like this one (I think he looks quite cuddly really) and then he finds Altos.
Barbara sees Vasor has a drawer with Sabetha's keys in it so she knows he is a baddy. He admits it. Ian also finds this out from Altos at the same time but in a different place, which is a clever piece of storytelling by Terry Nation.
Vasor attacks Barbara, but she lets Ian and Altos in the house and they capture Vasor and make him take them to where Susan and Sabetha are. Susan and Sabetha are in a cave. They are lost, but no wolves or polar bears come to get them.
They find a bridge and cross it (that's what a bridge is for, after all).
Vasor is scared and says there are demons in the cave. Ian, Barbara and Altos find the same bridge and cross it, finding Susan and Sabetha on the other side. But Vasor is still a baddy and he drops the bridge so everyone except for him is trapped.
Ian, Barbara, Altos, Susan and Sabetha find the key in a block of ice, surrounded by four statues of warriors. There is also a tap that turns the heat on and the ice begins to melt.
Ian and Altos improvise a new bridge. I don't know what it's made of.
Sabetha gets the key and then the statues come to life. It is a shocking moment when one of them opens its eyes.
They all run away. Ian fights the warriors while Susan crosses the new bridge. This is a very tense scene - bits fall off the new bridge, but eventually Susan gets across. She puts the old bridge back up so the others can cross, then Ian takes it down again so one of the warriors falls down into the hole.
The other warriors are confused. They can't talk but if they could I think they would say "where did our bridge go?"
Ian, Barbara, Altos, Susan and Sabetha get back to Vasor's hut to get their teleport bracelets back from him. They must have forgotten about them when they captured Vasor earlier, but that is understandable because they were worried about Susan and Sabetha.
Vasor threatens Susan but the warriors turn up (maybe they jumped across or maybe they improvised their own bridge, I don't know I'm just a cat) and kill him. Ian, Barbara, Altos, Susan and Sabetha teleport away so the warriors can't get them.
Ian appears in a room where there is a manny on the floor, I think he is having sleeps. Ian sees there is a key in the room. Another manny knocks Ian out and then steals the key. We don't find out who this mysterious manny is because that is the end of the episode.
This is a very fast-moving episode with lots happening, and it really builds up the tension towards the end, though a lot of that would not have been there if Ian, Barbara and Altos had remembered to take the teleport bracelets with them to the cave. Silly mannys.