The set-up for the Netflix comedy series Murderville requires a voiceover explanation at the beginning of every episode, but it's not as convoluted as it initially sounds. It's a cop-show parody starring Will Arnett as the pathetic yet self-important Senior Detective Terry Seattle, who works in the homicide division of an unnamed city -- that's definitely not Seattle. In each episode of Murderville, Terry is assigned to solve a murder, and his partner is a different celebrity guest star. Those guest stars aren't playing cops who are Terry's partners: they're playing themselves and improvising their way through each episode.

Terry and his colleagues guide the guest stars through the murder investigation. At the end of the episode, the celebrity deduces which of the three suspects is the murderer. Along the way, the guest stars are placed in awkward situations in the name of "investigating" the murder, forcing them to behave ridiculously and roll with whatever Arnett and the other actors throw at them. It's a combination of Whose Line Is It Anyway? and a murder-mystery dinner party. The concept is easy to follow once the first episode gets going.

RELATED: LEGO Masters Unleashes Evil Will Arnett In Exclusive Clip

One of the frustrating things about Murderville is that its concept may be too easy to follow. Since each episode unfolds according to the exact same formula, the only variation is how well each guest star responds to the absurdity. Not surprisingly, the best episodes in Murderville's six-episode first season feature guest stars with backgrounds in improv and who are willing to match or surpass Terry's antics. Kumail Nanjiani is the season's highlight, even coming up with his own running jokes that he returns to in response to Terry's bizarre demands.

Will Arnett and Kumail Nanjiani in Murderville

Conan O'Brien also fares well. Fellow comedy star Ken Jeong is unexpectedly unenthusiastic, demonstrating one of the show's main weaknesses as he spends almost his entire episode laughing at Terry and the other characters. Unlike Whose Line Is It Anyway?, which is performed on a stage in front of an audience, in short, silly sketches, Murderville is set in its own fully realized fictional world, with a supporting cast and ongoing storylines. So commitment from the guest stars is key, otherwise, the flimsy narrative structure falls apart.

RELATED: Eternals' Kumail Nanjiani Was Almost Cast in a Very Different MCU Movie

The season's low point comes in the second episode, with former NFL player Marshawn Lynch as the guest star, spending most of his time just gawking at the show's goofiness. Arnett is a charismatic, funny performer who can carry an entire show on his own, but he shouldn't have to -- especially when he's stuck holding up both parts of a scene. The supporting cast, including Haneefah Wood as Terry's boss and estranged wife, is amusing, but they're mostly stuck playing it straight opposite Arnett's blustery, buffoonish Terry.

Will Arnett and Conan O'Brien in Murderville

Murderville is based on the British series Murder in Successville, which followed a similar improv-based format and ran for three seasons. That show's high concept also included a city populated by "celebrities" played by sketch-comedy performers. However, Murderville's city and its murder victims are disappointingly mundane.

Murderville was developed by Krister Johnson, a writer and producer on Adult Swim comedy series Childrens Hospital and its Netflix spin-off Medical Police. He casts a number of Childrens Hospital veterans as the various suspects, including David Wain, Erinn Hayes, and Rob Huebel. Those actors provide occasional extra laughs, but Murderville's rigid format doesn't allow it to explore the comedic absurdity that made Childrens Hospital hilariously unpredictable for seven seasons.

RELATED: Is Schitt's Creek the Perfect Progressive Sitcom?

Instead, celebrity guest stars including Sharon Stone and Schitt's Creek's Annie Murphy are put through familiar improv exercises like mirroring, accents, and voice modulation, in approximations of the kind of games that would take up a few minutes on an episode of Whose Line Is It Anyway? But Murderville's episodes run 30 minutes or longer, quickly exhausting their comedic possibilities.

Murderville's episodes then turn into exercises in clue-gathering so that the celebrity guest can offer a solution at the end of the episode. As with its improv comedy, the dedication to this portion of the show varies from guest to guest. Murphy presents such a detailed analysis that the actual reveal mostly repeats what she said. Jeong demonstrates the same lack of commitment to mystery-solving that he brings to the comedy bits.

There's a certain appeal to watching charismatic celebrities goof off. In its best moments, Murderville captures that sense of fun. But it too often comes off as if its celebrity guest stars wandered into an improv class without any preparation, and they're just marking time until they can go home.

The six-episode first season of Murderville premieres Thursday, February 3 on Netflix.

KEEP READING: Netflix's The Woman in the House... Runs Wild With Deadpan Thrills & Chills