Just three minutes into this episode, it's possible that Snakedance has the most compelling opening of any story seen for some time. Look at the first scene - a short scene consisting of 4 static shots of a man sitting cross legged on a mountain, each shot moving in closer and closer to a strange crystal hanging around his neck.
Then boom! Cut to the TARDIS interior, with a newly garbed Nyssa coming through the door, her first line interrupted immediately by The Doctor blurting out, "We're not where we're supposed to be." Bam! In less than 15 seconds, it's pointed out that the TARDIS has landed somewhere where it shouldn't have, and that The Doctor is quite concerned. In most stories, there's the usual banter back and forth in the console room, the TARDIS lands, The Doctor and his companions get out and explore, only then learning that they've landed in the wrong place. Meanwhile, other characters become involved in the plot long before The Doctor does.
But not here. Soon after, we're introduced to what looks like a privileged young man, strolling lethargically down a spiral staircase and plopping himself down on a sofa, staring blankly at a statue of a snake while wondering why he bothered to get up in the morning. That's our introduction to Lon, who will become the main antagonist, it would appear. An introduction with no words, yet one that says so much.
Within those first three minutes, because of the pace and the economic storytelling, I am immediately hooked. Whether it's down to the writing of Christopher Bailey or the direction of Fiona Cumming, the results are superb.