Frostfire is the best of the first four. Marc Platt is the author: he lands the Doctor, Vicki and Steven in the frozen London of 1814, where they team up with Jane Austen - Jane Austen - to defeat a nefarious force that threatens to suck the energy out from the whole of London, and maybe the world. Platt and through him Maureen O'Brien (playing Vicki for the first time in over forty years!) between them catch the First Doctor's voice perfectly, though poor Steven doesn't get much to do. It's nice to have a framing narrative of Vicki - now Cressida - reminiscing about the events of years before, for her subjective time line, or three thousand years in the future, by Earth time, and it turns out to have more relevance to events than anticipated. There is a typical Marc Platt paradox by way of plot resolution, and you have to swallow the concept of Jane Austen as woman of action, but it is tremendously enjoyable. ( )