What We Do in the Shadows is one of those conceptual comedies with a limited premise that you expect to die off at any moment, but it keeps coming as though it doesn't know how to die. I guess that's an apt comparison since the FX series is about the undead, but there might be another explanation: It's just funny.

When the adaptation of Taika Waititi and Jemaine Clement's mockumentary film about incompetent vampires was announced, I thought, "Hey! I liked that movie a lot!" But I also remembered the movie didn't really have a whole lot of plot, just a non-stop run of vampire gags. That's gotta be a concern when blowing the movie out into a full-fledged television series, but it apparently wasn't much of a concern for Waititi and Clement — who executive produce, write, and direct parts of the series — as the show is a true adaptation of the movie down its high-concept premise (vampires!) laid over a much simpler premise (they're roommates!).

Kayvan Novak, Harvey Guillen and Matt Berry, <em>What We Do in the Shadows</em>Kayvan Novak, Harvey Guillen and Matt Berry, What We Do in the Shadows

Which is why it's impressive that the first four episodes that FX sent in advance have so much life to them, despite the limitations of the series (or does its nebulousness make it unlimited? Hmmm...). Like the movie, a documentary crew follows a trio of vampires who live in an old house and suck the juices out of local townsfolk — the series moves the location from New Zealand to Staten Island — and their ancient ways clash with modern times, like when one has to sign for something on an iPad but his touch doesn't register on the screen. That sounds like it would make for a good Saturday Night Live skit, but a couple things make What We Do in the Shadows break the curse of "Why did this one joke get made into a whole series?"

First, the cast is superb. Kayvan Novak, who's been in a slew of great British comedies like Inside No. 9 and Rev, plays Nandor the Relentless, who used to be a warrior in the Ottoman Empire before he was vamped, and is just as defined by his light lisp as the way he's softened over the centuries into a sensitive head of household more interested in keeping the place tidy than enslaving humanity. Fellow Brit Natasia Demetriou is Nadja, who isn't as old as Nandor but acts as though she's lived twice as long and is over it all, particularly with her marriage to Laszlo, a boisterous and pompous vampire played by the inimitable Matt Berry (The IT Crowd, The Mighty Boosh). Each of them, in their ridiculously garish old-world costumes of cloaks (and occasionally armor), are a delight in everything they do. They're joined by Nandor's human familiar and wannabe vampire Guillermo (a very funny Harvey Guillen), a sheepish goober waiting for Nandor to give him the curse of immortality.

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But the real MVP is Mark Proksch (Better Call Saul's nerdy drug-dealing pharmacist Pryce), whose character Colin Robinson is the biggest change from the film. Colin is an energy vampire, which is apparently an actual thing in folklore but also a dysphemism for an incredibly boring person, and he goes about feeding not on blood, but on the joy of others by talking about car insurance, his dying uncle, or whatever else sucks the life out of a room. I'm sure he'll be recapping NCIS to others at a later time in the series. At this point, you should know that What We Do in the Shadows doesn't really care about mythology, and that's totally fine because watching Colin move through his office while mentally destroying his coworkers with mundane factoids is more terrifying than anything a horror film can produce.

WHAT WE DO IN THE SHADOWS -- "Pilot" -- Season 1, Episode 1 -  Pictured (l-r):   . CR: John P Johnson/FXWHAT WE DO IN THE SHADOWS -- "Pilot" -- Season 1, Episode 1 - Pictured (l-r): . CR: John P Johnson/FX

What We Do in the Shadows' aesthetic and effects also helps keep the blood flowing. It's dark, obviously, and dusty, but not in a haunted house kind of way, more in a "this place could use a housekeeper" kind of way, highlighting the mundane lives these vampires are living. The special effects are also intentionally not really that special at all, adding a DIY charm to the supernatural comedy. A werewolf after a full transformation looks like something that would be eliminated in the first round of Face Off or something almost impressive but too crappy to pay much money for from a costume store. And when Laszlo says, "Bat!" every time he blinks into a bat, it's all the show needs because it's funnier than anything that required any more time in a video editing program.

But even after four pretty funny episodes, I question how long the show can do this without the larger arcs we're used to from FX's recent comedies. There's one continuing thread inching along about a virginal LARPer who gets turned that has plenty of legs should the series continue to pursue it, but most everything else is built around the vampires repeatedly proving they're everything but dangerous to humankind's grip on the planet, and the relationship dynamics between a master and slave (Nandor and Guillermo) and a long-term couple (Nadja and Lazslo). But rather than worry about it running out of juice, I'll just suck it dry until there's nothing left.

What We Do in the Shadows premieres Wednesday, Mar. 27 at 10/9c on FX.