Only five more to go.
Season Sixteen ushers in not only a new mark of K-9 and a new companion, but also, courtesy of producer Graham Williams, a season-long story arc that sends the Doctor on an extended quest for the Key to Time. This meta-narrative serves to loosely tie together six otherwise disparate stories by giving the Fourth Doctor and Romanadvoratrelundar (Mary Tamm) some McGuffin to track down in each tale. But more importantly, as series veteran Robert Holmes’ “The Ribos Operation” (Story Production Code 5A) demonstrates, the story arc allows for smaller scale adventures for the Doctor; the fate of the known galaxy isn’t immediately at stake in this four part story, just the lives of two con men—and those of the two Time Lords who get caught up with them.
To establish the overall season arc, a bumper scene shows the TARDIS halted in mid-flight, the doors flung open in a splay of harsh golden light. Tom Baker manages to convey the Fourth Doctor’s trepidation well, despite heavy make-up covering facial injuries suffered prior to shooting this episode, convincing the audience that the otherwise inoffensive gentleman lounging in a wicker chair like some minor functionary of the Raj at a Bombay club wields untold power. The White Guardian (Cyril Luckham), as he describes himself, sets for the Doctor a task he cannot refuse, to secure the six segments of the Key to Time, claiming some cosmic catastrophe should he fail or, worse, should the Black Guardian acquire the pieces instead. The stakes, essentially, ratchet to the highest possible level—total annihilation of everything. Even for Doctor Who, that’s a step beyond the typical conundrum of Dalek conquest or planetary plague.
The White Guardian assigns the Doctor an assistant, against his wishes, leading to the presence of Romana, a recent graduate of the Time Lord Academy and a mere stripling at 139 years old, against the Doctor’s 759 (or so) years. She indicates that she was picked by the Supreme President of the Council (a position the Doctor held one story prior), suggesting that the Time Lords as a whole adhere to the wishes of the Guardians, a heretofore unknown power, or at the very least know better than to defy them. (Granted, the Time Lords were almost undone by telepathic tin foil and a grand total of four Sontarans in “The Invasion of Time,” but they still remain a potent force in their own right. Really.)
With the overarching quest providing the narrative urgency, as it were, the stage is set for the Doctor and Romana (with a little firepower from K-9 Mark II as needed) to have a small, intimate adventure, of a kind last seen with any frequency when William Hartnell’s First Doctor was trodding the boards at Television Centre. The tracker Romana installed in the TARDIS, without the Doctor’s permission, leads them to the planet Ribos, a “protected class three” planet whose civilization exists at a primitive level, firmly convinced that their world is flat and the stars but floating ice crystals. All the Doctor and Romana must do is procure the first segment of the Key to Time, which happens to be hidden as some other object inside a guarded case holding the planet’s crown jewels. Easy enough for two Time Lords armed with a Sonic Screwdriver, except someone has already broken into the case…