America’s fascination with true crime is played for satire in the dark comedy “Based on a True Story,” a Peacock series starring Kaley Cuoco and Chris Messina as a married couple who, dollar signs in their eyes and bad judgment in their hearts, seize upon the opportunity to make a podcast with a serial killer.

Tonally, the eight- episode series teeters between slasher territory and the humor of domestic ennui. Ava and Nate’s marriage has grown stale, their professional ambitions thwarted. She’s a real estate agent who struggles to land high-end clients; he’s a tennis pro at the Beverly Club who has been demoted. This is an upper-middle-class kind of frustration, and while the show hints at some class issues, it doesn’t go far enough. They’re also expecting their first child (the show incorporated Cuoco’s real-life pregnancy), though it’s unclear how they feel about becoming parents. They seem neither excited nor anxious.

Stalled careers and annoying home repairs have made life dull, but the couple isn’t in desperate straits. They’re just restless and unhappy. So Ava seeks refuge in true-crime stories, and when she and Nate suspect a new acquaintance might actually be a serial killer dubbed the West Side Ripper, a proposal is hatched: What if we made our own podcast, where the killer shares all but remains anonymous? It’s never been done before; surely riches will follow.

In over their heads, Ava and Nate are continually yanked around by this unpredictable man. The threat of violence is always hovering around the edges and, as a result, Cuoco’s performance involves a lot of “shocked face.” As a character, Ava is too underdeveloped, floating prettily through what she sees as a boring existence. Messina gets more to play with, as a man with a deeper, angrier sense of middle-aged resentment that he barely keeps suppressed.

Their main competitors in the podcast world are the wonderfully ludicrous Sisters in Crime (played by June Diane Raphael and Jessica St. Clair) who confidently assert that the great American art form isn’t music or film or television. No, America’s great art form is murder: “We watch it. We celebrate it. We obsess over it. And we commit it.” That captures the show’s approach, which is ridiculous and occasionally menacing but also entirely plausible. All the same, “Based on a True Story” isn’t looking to examine any of these ideas so much as play them for comedy and horror.

It’s an approach that’s propulsive and keeps you guessing, both skewering the ghoulishness of true crime while also indulging in it. That’s a neat, if somewhat dubious, trick. I like the show overall, but it doesn’t hold up to scrutiny. That’s OK — it can exist purely in the realm of upbeat, if sinister, high jinks, so long as we’re not pretending it’s saying something more.

Ava and Nate’s story is forever unraveling, and it might have benefited from a clearer sense of what these two hope to achieve with the podcast. The season ends on a cliffhanger, which I think is a mistake in the streaming era, with the uncertainty it has foisted upon the TV landscape.

What about the podcast itself? We don’t hear much of it, or see the work that goes into putting it together (a task that is harder than the show would lead you to believe), but the killer is unhappy with an early edit and has plenty of ideas of his own. He’s trying to protect his brand “and you keep wasting time cutting to these other characters,” he says with some annoyance. The victims’ families are just a distraction from the main event.

What a savage comment on how hollow many of these projects actually are.

How to watch: Peacock