The light returns to 80s Doctor Who.
Further proof of the magic that finally returned to Doctor Who after a long battle with mediocrity through most of the late 70s and early 80s. Seasons 25 and 26 introduced some of the most complex concepts of all of Classic Who with hardly a fault (save for large chunks of Silver Nemesis).
Ghost Light is a complicated beast, put succinctly in Martin Day, Keith Topping and Paul Cornell's The Discontinuity Guide '...in order to appreciate fully what's going on it is probably necessary to watch Ghost Light two or three times.' This is true to some degree, but there is more than enough to garner from the story on first viewing. This is a story that competently tackles a myriad of ideas and even interpretations of the Doctor Who mythos, something that almost NEVER works in the classic series. Ideas such as "Light" and "Control" being real, physical beings that can interact and exist to us is handled incredibly well, focusing these characters into depictions of Victorian values that, up until this point in the show, weren't as thoroughly demolished through criticism and light scepticism of their ideals and standards (something the modern show has excelled at, as of late).
The relatively short serial tackles a really interesting combination of metaphor-as-narrative storytelling and the darker, but still light and bubbly tone of the McCoy era, which fold onto each other in ways that don't often get presented in the show, let alone most shows.
The continuation of Season 26's ethos of "develop Ace more with each episode" isn't as strong as in the next serial (it's hard to compare anything with The Curse of Fenric, so it's hardly an issue), but there are further glimpses of Ace's clear flaws in an almost setting up of an arc to be followed through and completed in the final two serials.
McCoy's Doctor does exude an air of omniscience in this story, although more towards the final moments, which aligns with the unused ideas of The Doctor's God-like abilities being fleshed out for the unmade Season 27, but in this case this image of the doctor as the manipulator and the all-knowing all-seeing force of nature works into the favour of the serial, as if the overall story is punctuated by Gods and humans, the former battling it out for control, and the latter trying to simply get out alive, back into the light.