We have so many tropes here in this unexpectedly-spirited new arrival on BBC in early 2022.
We have the knowledgeable religious person (a nun who originated in series one of "Father Brown")
We have some kind of reverse Windrush Generation for 1960 - a detective from the West Indies, transferring in to Scotland Yard in London, who arrives on a (nicely-preserved) steam train in the west country village of Lower Slaughter (don't ask!) and settles into the ranks of the local constabulary.
The village detective depends upon the nun (who has a chemistry PhD and worked in Bletchley park during World War 2 (did I mention this is set in 1960?) Giving us some kind of reverse "death in paradise" homage to "In the heat of the night" (which would be filmed five years later...
And yet - it works!. Intellectually un-taxing, this is material and storylines which would probably pop up in the 8PM Sunday "Heartbeat" slot on British TV a decade back.
The early 1960s scene is beautifully crafted and, with a ten-episode first season (and confirmation in Q1-2022 that a series two will be commissioned) I predict that we shall be enjoying this 2020s creation for some time to come.
I wonder who will start the fanfiction storylines?