With his previous two series for Netflix – the Hauntings of Hill House and Bly Manor respectively – Mike Flanagan had already firmly established himself as one of the finest horror filmmakers of the modern era. And his refreshingly unique new series, Midnight Mass, will only further enhance that reputation when it arrives on the streamer this week. This seven-part series is a fascinating piece of work: imperfect, perhaps, and a little chaotic, but hugely ambitious, tremendously intriguing, and stuffed with some truly terrific performances.

Midnight Mass also differs from Flanagan’s previous TV output in that it is a wholly original piece, not based, however loosely, on an earlier work of horror fiction – as was the case with both Hill House and Bly Manor. There are shades of Steven King to the setup – and indeed King has already taken to Twitter to sing the show’s praises – but it becomes very much its own thing, especially as it builds towards its terrifically demented conclusion.

The series is set on Crockett Island, a rural, fiercely Catholic island community that is living under something of a cloud. On this rock resides a number of troubled and tormented souls: there’s the pious and unpopular Bev Keane (Samantha Sloyan), the proudly Muslim Sheriff Hassan (Rahul Kohli), and the drunken outcast Joe Collie (Robert Longstreet) – whose shooting accident led to teenager Leeza (Annarah Cymone) losing her ability to walk. And then there’s Riley Flynn (Zach Gilford), a recovering alcoholic who has just returned to the island after serving a four-year sentence for killing a girl in a drunk driving incident, and Erin Greene (Kate Siegel) his former schoolmate, pregnant with her first child and seeking refuge from an abusive relationship.

Each of these characters, crucially, has a different relationship to faith – and each of those relationships are put to the test when a new priest makes a sudden appearance at mass one morning, informing them that their long-serving Monsignor is stuck on the mainland after falling ill during a recent trip. This priest is Father Paul, played by Hamish Linklater in the show’s standout turn. Paul is an enigmatic, unconventional preacher – on the one hand inspiring and welcoming, and on the other rather crazed and despotic. Linklater plays him with a wonderful, unpredictable intensity – and viewers will find it near impossible to turn their eyes away from his performance.

Shortly following his arrival, strange happenings begin to occur – both negative (hundreds of dead cats wash up on the shore) and positive (the sick and infirm begin to make miraculous recoveries). The question is, can Paul be trusted, and is there something he’s hiding? To give too much more away would be to crossover into spoiler territory, but rest assured that things becoming increasingly hysterical and deranged the closer the series moves towards its conclusion.

To begin with, it can be a bit of a slow burn, and yet it’s still strangely propulsive – such is the intrigue that Flanagan has managed to weave into the story. The main power of the show rests in watching all of the island’s various inhabitants react to the incredible events that begin to take place, with their responses ranging from the fervent (Bev) to the extremely skeptical (Riley). This allows the show the chance to explore everything from faith to regret to loss to addiction.

And there aren’t always easy answers: it’s the kind of show which is confounding in the best possible way – not everything is explained, and nor should it be. But its success lies in the fact that it’s grounded in characters and settings that feel totally real, and it seems certain to reward repeat viewings. There are also some tremendously atmospheric sequences: for example, Flanagan makes good use of traditional hymns in the soundtrack throughout, perhaps most notably of all in a stunningly haunting candlelit procession to the church in the penultimate instalment.

Although it would be easy to be uncritically evangelical about the series, on first watch I did think it imperfect. The scope and scale of the hysteria that grips the island is impressive, but at times it felt a little too messy, a little too chaotic for its own good – it throws everything at the wall, and I’m not sure everything sticks. Meanwhile, as well-drawn as the characters are, some of the dialogue – especially in the early episodes – can be a touch too expository and on the nose for my liking.

I also think it’s worth noting that although there’s undoubtedly a feeling of deep unease across each of the seven episodes – in addition to a handful of jump scares and no shortage of blood and gore – I didn’t find the series quite as terrifying as Bly Manor or Hill House, the latter of which remains my favourite Flanagan series to date. That’s not necessarily a bad thing – just to say that this is a rather different type of horror to the ghost stories that Flanagan has gifted us with in the past.

Anyway, whatever minor shortfalls there might be, Midnight Mass is absolutely a show worth watching. It’s genuinely, thrillingly, unique and certain scenes and moments will live with you long after you’ve finished watching. One thing is for sure – Flanagan remains comfortably one of Netflix’s best assets.