I've already mentioned the scene in this episode between The Doctor and Romana in captivity, but it bears mentioning again if only because it's just so damned sweet. One can't help but feel all warm and happy watching Tom Baker and Lalla Ward patch up whatever disagreement they may have had during the production of this story (well, really, whatever disagreement they were having since they met in 1979). You'd almost think that Baker proposed to Ward before the camera rolled.
There's an incredibly long scene involving The Doctor and K-9 hypothesizing about vampires that takes up a good chunk of this episode, consists almost entirely of Tom Baker reading vampire legends off of ticker tape to K-9 (well, himself, really), and it's utterly enthralling, once again proving that more often than not, the best actor to compliment Tom Baker is Tom Baker. Even Peter Moffatt, who is positively inspired in this, uses a small crane shot to include, for the first time ever, Tom Baker and the K-9 prop in the same shot without having Baker kneel down.
Another great, spooky episode which ends with a completely unnerving smile on Zargo's face that I won't soon forget.