Genesis of the Daleks
The famous Genesis of the Daleks, so often held up as one of the best Doctor Who stories, if not the best ever. I'm not sure if I'd go that far, but it was pretty good.
On its own merits, it was a pretty interesting story, depicting the (literal) space Nazi origins of the Daleks, the civil war on Skaro, the disagreements even within the Kaleds over the future of their race (though everyone seems pretty chill about one day mutating into a green octopus). Grim as fuck, particularly the ending, which was great. Davros is also a really fascinating character, as he relates to the Daleks, the Doctor, the Kaleds -- he's on no real side but his own, and the way that plays out to his benefit and detriment is really interesting to see. Michael Wisher's performance as Davros is also *fantastic*.
But, as a Doctor Who story though, I'm not sure what to think of it. I don't necessarily think that the Doctor needs to change history and actually affect the outcome of a story for it to feel like a significant Doctor Who story. I think there's value in seeing the Doctor trying but failing to change things for the better; there's some drama to get out of that, and this story certainly does so with a couple great conversations between the Doctor and Davros as well as the Doctor's own monologue about whether he has the right to commit genocide when, at that point in time, the Daleks hadn't done anything to deserve it yet (I appreciate the morality play but frankly I find the Doctor's position here really irresponsible and inexcusable, especially his rationalization later that if there were no Daleks, then other planets/races wouldn't have a common enemy to unite against).
Still, something about the fact that the Doctor having no real impact on any of this -- that if he hadn't gone to Skaro in the first place everything would've still stayed the same -- kind of rubs me the wrong way. This was also my first Tom Baker serial, which in hindsight might have been a mistake, because this story is way less about the Fourth Doctor than it is about Davros and the Daleks. On a separate issue, I also never really found the subplots with Sarah and the 'mutos' engaging, though that's not really a big deal.
Despite some quibbles, it was a really good story with some very interesting food for thought. Next up: City of Death