The beginning of the end for the Fourth Doctor! I believe that this was the only full story of Season 18 I had already seen from the Twitch marathon, and I thoroughly enjoyed it - it seems that this time around, it held up to its high standards.

It's hard to see how Tom Baker wasn't having fun in Season 18, because even in his penultimate story, he's giving the role his all. He clearly adores the show so much and that makes the episode a lot more enjoyable for the audience. The Doctor's relationship with Adric is strengthening now Romana has left, almost like a teacher-student relationship. Adric didn't side with the villains for once! Hooray! He's actually the most bearable he's been in his entire run and for once I didn't want to punish him. The way he interacts with Nyssa is great, he's clearly made a close friend who he gets along with, both being fairly young and relate to each other.

Isn't it strange that the Master only is on screen for like 10 minutes? Like you can hear his voice and see his TARDIS throughout, but he only actually shows up for a confrontation with the Doctor. There's a lot of setup and hints towards the Master returning, such as the energy generator being on a similar wavelength to a TARDIS. After quite a lot of duds featuring Geoffrey Beevers as the Master in the Fourth Doctor Adventures, I'm glad that there's finally a story which does this incarnation justice - it's just a shame he doesn't show up until Part 4, but at least he's got a new body... at last.

The sets look fantastic - the grove is beautifully realised, the Traken buildings match the gothic tone as well as creating an alien atmosphere to explore, and it all looks very realistic for 80s who - they even went as far as to add a bit of the alien sky in the background rather than just black! The set designers went all out for this episode, and it really pays off - and Melkur looks awesome too!

Poor Tremas - Anthony Ainley gets a chance at playing a nice, warm scientist and father - helps to ground new companion Nyssa - and then he gets killed off and replaced by the Master. It was very interesting that, in Nyssa's introductory story, they focus more on her father than her. That's why I'm not really going to be talking about Nyssa as a companion until Castrovalva. Kassia is hilarious, because the actress is trying way too hard and it's hilarious - she keeps pulling this one face which is just ridiculous and passing out for no reason, it's the stupidest thing ever but I lowkey love it.

I adore the score for this episode, it's so calm and relaxed, but at the same time has an undertone of evil surrounding it at certain points - it's so quintessentially Classic Who, and I think it's the definite article of music from this era.

This is a really strong story, as has been most of Season 18. This story gets better with each watch and every time you notice something new that you didn't before - this is a cleverly written script with amazing visuals, from a relatively unknown writer - I'd love to see more from Johnny Byrne!