A priest arrives on remote island to replace the previous priest who, very elderly, had gone on a pilgrimage to Jerusalem and suffered some unspecified type of health breakdown. The old priest is supposedly on the mainland recuperating; the new priest, Father Paul Hill (played by Hamish Linklater) is a locum, until the old priest gets better.
There's a twist in the basic way this story is delivered, which I'm now going to spoil for you. For the first three episodes Midnight Mass is a slow-burn study of a religious revival, centring on young Father Hill's charismatic ministry and his ability to perform literal miracles, such that the lame can walk and the elderly start to grow young again. Then the twist in episode 4: the young priest is the old priest, rejuvenated. In Israel he passed from the centre of Jerusalem into a huge, peopleless desert by walking for a few minutes, which seems topographically improbable to me, but what do I know. Out in the wilderness at night he was bitten by an ancient, leathern-winged monster. Rejuvenated by this envampirication, Father Hill has travelled back to the island carrying the old leathery dracul with him in a big suitcase.
Since then Father Hill has been adulterating the communion wine with his own vampiric blood, thereby passing vampireness, or vampirosity, in vampricially small quantities to the whole population, which explains the apparent miracles. Meanwhile old leatherwing has been flying around at night doing all the things antique vampires like to do: drinking cats, peering in at windows and occasionally killing people. The remaining three episodes of the drama switch sharply into schlock-horror territory: Father Hill, abetted by some of the islanders, plans on turning everyone into vampire. They burn all the boats so no-one can get away, summon everyone to church for the titular Easter midnight mass and then lock the doors. There's a lot of biting and screaming and blood squirting and running around and stuff.
Twists are tricky things, storytellingwise. They can be cleverly deracinating step-changes in the logic of a text, that make you re-evaluate everything you thought you knew. Or they can be daft, ‘you've been tango'd!’ face-slaps. I had no sense of this Netflix series before watching it, beyond knowing that it was by the Haunting of Hill House geezer, so the ‘oh, it's vampires!’ stuff did surprise me, pleasantly enough. But the twist soon sours, tending to banalise the previous, more carefully observed and unusual drama, and jolting the whole into something far pulpier. It doesn't help that the whole vampire conceit is treated so sloppily.
So, as per your standard vampire movie, sunlight scorches and burns these vampires. Indeed the story's big denouement is that, having turned everyone (except two of the more likeable teens, who escape in a canoe) into vampires, Father Hill and his cronies are caught out: in the orgy of destruction all the island's houses have burnt down and now, as dawn comes, there is nowhere to hide from the sunlight. Oh no! Not one shady spot with covering foliage, not one cave, no cars or vans, not so much as a single tarpaulin (on an island whose economy is fishing, don't forget) to pull over oneself until the comfort of dark: nothing! So all the vampires instantly burst into fire and crumble to dust as the first rays of the sun strike them. But wait: Father Hill himself has been fully vampire for months and months, so much so that he is entirely rejuvenated, and in the show's early episodes he walks around the island cheerfully in full daylight. Some of the islanders, having drunk priestly blood, now cannot be killed, a fact demonstrated with various stabbings and shootings from which they resurrect. Others who have also drunk the priestly blood, but who are pegged as ‘good’ characters, arbitrarily, by the writing, can be killed, and are.
The story also suffers badly from the Ambridge problem. I mean: the way Ambridge is the only village in England in which nobody listens to The Archers. Here not a single character at any point goes ‘you mean they're ... vampires?’ Nobody mentions Christopher Lee or Twilight or What We Do In The Shadows. The island doctor makes an awkward speech about some strange parasite causing combustability of blood, and none of her audience go: so, vampires. Perhaps Flanagan thought stating the bleeding obvious here would demean the more pretentiously grandiloquent ambitions of the piece. A bum call, I think.

