Free of companions aside form loyal robotic K9, the Doctor sets off free to go where he wants, but finds himself drawn to a strange place where he meets a man in an Emmanuel wicker chair sipping on a green cocktail. With none of this giving him pause, the Doctor accepts a task from this so-called 'White Guardian', to recover six hidden parts of the powerful Key to Time. To aide him with this he is connected with Time Lord Romanadvoratrelundar, whether he wants her as a companion or not. The two head off to the planet Ribos where they realize that the most likely piece of the Key to Time is actually being used in an elaborate con targeting exiled tyrant Graff Vynda-K.
The start to this season is quite interesting as I think it is the first to lay out the potential for a season-long narrative which holds all the individual series together, although one could argue that similar threads were loosely used in the UNIT era. That said, it is not the best setup as it is all just dropped in out of nowhere, looks cheap as a set, and has the constant distraction of why the Doctor has an odd mark on his lip (turns out Baker had been bitten by a dog). Likewise the new assistant is just dropped on him and there is a bit of a feeling of it all being rushed. Perhaps it comes with the territory, since the show is keen to get into the serials, and so it does with the Ribos Operation.
This plot is reasonably simple on the face of it, but the simple con is not particularly sharply delivered and feels messy and a little drawn out. Once I got into it, it felt a bit clearer and more enjoyable, but it remained a bit messy and not as smart as it could have been. There is a decent mix of humor and action in there, but all in all it wasn't particularly captivating in the broad sweep. The characters are mostly enjoyable; Baker is on decent form, but doesn't really make a connection with Tamm. She appears to have understood that the character is the equal of the Doctor in terms of species, but yet is not given material to show this – so she ends up being very much like other companions but her performance is quite snobby. Cuthberston, Plaskitt, and Seed, are enjoyable throughout, although the best character is Bateson's Binro, who is very well written and performed.
The sets and costumes are good, with only the brief views of the shrivenzale being a bit comical. Mostly it plays out as a decent episode with some good ideas and enjoyable elements, even if it doesn't flow or stick in the mind as well as it really ought to have.