Sometimes a TV show is ambitious and foolhardy enough to attempt a true slow burn — taking the risk of alienating both critics and viewers by parceling out its secrets with uncommon patience over the course of a full season. Fortitude is just such a show.

Fortitude has quietly evolved into the best new show of 2015. When it premiered on Pivot in January, I called Fortitude "another grim TV murder mystery" (albeit a very good one). There was nothing in the three episodes I'd seen to make me believe the show was aiming to be anything but another solid entry in TV's ever-growing stable of well-heeled crime dramas, in which a glowering detective uncovers the deep, dark secrets of a small town on his way to solving a grisly murder.

Consider this my mea culpa. Over the remaining nine episodes of its 12-episode first season, Fortitude has consistently tangoed around my expectations, getting deeper and tenser and weirder and altogether more mind-boggling with every episode. If you're not watching Fortitude yet — and based on the deafening lack of culture buzz, you're probably not — catch up now, before the rest of the internet catches on and spoils it for you.

Maybe you're already convinced. If so, great! You can stop right here. Go watch the whole season. (If you don't have Pivot, there are still several places to watch.)

If you're not convinced yet — well, now I need to explain why Fortitude is so good without spoiling any of the things that make it so good. Let's start with the setting, which gives the show both its title and its thematic underpinning: Fortitude, a small international community located somewhere way, way up in the Arctic Circle.

Though the permafrost makes for a gorgeous and fascinating backdrop, it initially feels a little like a gimmick — just a cold-as-ice variation on the "small town with secrets" thing that's already been explored in shows like Twin Peaks and Broadchurch. It's only later that the feral, claustrophobic reality of the setting starts to close in. For most of human existence, the area on which Fortitude was built was literally inhospitable — a frozen wasteland prowled by polar bears. A combination of technology and sheer will led to the town's unlikely creation, but nature is pushing back. It becomes increasingly clear that Fortitude's pilgrim citizens are fighting a losing battle against an unknowable, uncanny force, and that the murder that kicks off the series is just a tiny symptom of an infinitely more horrifying reality.

In Stanley Tucci, Fortitude gives us an ideal leading man to navigate this nightmare. His DCI Morton — the out-of-towner assigned to investigate the murder that kicks off the series — learns the ins and outs of Fortitude at the same time as the audience. Tucci is the rare actor who elevates every single project in which he appears, and it's hard to imagine an actor better suited for the role of Morton, who seems like he would be right at home in a list of TV's never-ending stable of brilliant, unflappable detectives, sandwiched alphabetically between Morse (Inspector Morse) and Murdoch (Murdoch Mysteries).

But Fortitude is smart enough to understand that no one — not even someone as experienced, controlled, and driven as Morton — is prepared for what's really going on. It's a canny inversion of a tired TV trope: a case in which the brilliant detective's well-earned confidence is an Achilles heel, driving him further and further astray from something that has no precedent in anything he's seen before.

Tucci is just one of many underutilized character actors who Fortitude pivots to the center of its narrative. Richard Dormer, best known as Game of Thrones' Berric Dondarrion, is terrific as Fortitude sheriff Dan Andersen, whose perpetual grin masks both his vulnerable side and his animal side. Sofie Gråbøl, star of the Danish TV series Forbrydelsen (which was later adapted into the inferior The Killing), is stoic and decisive as the town's ambitious leader. As a drunk, dying photographer with a closet full of skeletons, veteran actor Michael Gambon is weird and maddening and heartbreaking — a man whose desperate, last-ditch attempts to atone for his sins only leads him to commit more of them.

What else can I say without spoiling the fun of letting Fortitude slowly work its magic on you, as it worked on me? Not much. Let's just say that at varying points in its narrative, Fortitude recalls the best parts of Twin Peaks, Fargo, and True Detective, using the lessons of the TV shows that came before it to spin its own unique and mesmerizing tale.

Fortitude hasn't been renewed for a second season — and while tonight's season finale might turn out to be a series finale, I'm not writing this as a last-ditch attempt to drum up buzz for a show that's on the bubble. As a fan of quality television, I'd be thrilled to see Fortitude get a second season, but I'm not sure it needs one. If this is the last hour of Fortitude we ever get, the show has already carved out its own fascinating niche in TV history. I'm glad I got to be surprised by it. Don't miss your chance to experience the same.

Update: Since this story was posted, Fortitude has been renewed for a second season.