"Do you dare step through the red door?"
That's the opening hook Koontz gives us, and honestly? It's the most restrained thing in this entire 24-hour behemoth of a novel. I was shelving returns at the library on a Wednesday afternoon when I first queued this up, thinking I'd chip away at it over a couple weeks. By hour three, I'd forgotten what I was doing with my hands and had misshelved an entire cart of YA into the biographies section. Nobody noticed. Small-town library perks.
So let me be straight with you: Dark Rivers of the Heart is a deeply frustrating listen, because it's about 60% excellent thriller and 40% Koontz refusing to get out of his own way.
Roy Miro Made My Skin Crawl (And Not Always in the Good Way)
The villain here is where this book earns its horror credentials, and where it loses some readers entirely. Roy Miro — government operative, self-appointed angel of death — is the kind of character who strokes a woman's hand while contemplating her murder and genuinely believes he's doing her a kindness. That specific blend of tenderness and psychopathy is hard to pull off without tipping into cartoonish, and Koontz walks that line with surprising skill. The sections inside Roy's head are genuinely unsettling, not because of violence (though there's violence), but because of the absolute conviction Roy has in his own compassion. This understands that horror isn't about gore — it's about dread. The dread of someone who has completely rationalized evil as mercy. That particular flavor of dread — mundane evil wearing a gentle face — is something All That Remains also gets into, though with a very different kind of investigator trying to make sense of it.
But — and here's where it gets messy — Koontz spends SO much time in Roy's perspective. Page after page of his internal philosophy, his justifications, his creepy little meditations on beauty and death. Some listeners have said the villain's ideals "hit too close to home," and I get that. It's uncomfortable by design. But there's a difference between uncomfortable and indulgent, and somewhere around hour fourteen, I started to feel like Koontz was more fascinated with Roy than the story required.
Spencer Grant and the 24-Hour Slow Chase
The protagonist, Spencer, is a man running from both a shadowy agency and his own buried trauma. He's got a dog named Rocky (instant points), a mysterious woman he barely knows, and a past that keeps surfacing in fragments. The structure is classic Koontz — parallel pursuit narratives, the net tightening, revelations doled out in careful intervals.
The problem? At nearly 24 hours, this audiobook tests your patience. The pacing lunges forward in these incredible bursts of tension — car chases through desert landscapes, narrow escapes, the SWAT raid on the bungalow early on that kicks the whole plot into gear — and then pumps the brakes for extended passages of description and backstory that feel like Koontz hit his word count and kept going. I found myself toggling to 1.25x during some of the middle sections, which helped enormously. If you're the type who needs momentum, adjust your speed and don't feel guilty about it.
What works, though, really works. The paranoia is excellent. The shadow agency that "answers to no one — including the U.S. government" felt prescient when this was published in the '90s and feels even more unsettling now. And Spencer's fractured memories — the way his past bleeds into the present — give the book its emotional spine.
Scott Merriman Carries the Weight
The narrator commits. That's rare. Merriman has an Earphones Award, which tracks — he handles this sprawling cast with a steadiness that a lesser narrator would've buckled under. Twenty-four hours is a marathon, and there are sections where the prose gets dense and interior and a bad narrator would've turned it into white noise. Merriman keeps the tension coiled even when Koontz's writing goes slack.
I wish I had more specifics on his character voices — the research didn't give me much to work with on differentiation — but what I can tell you is that his emotional register shifts cleanly between Spencer's guilt-soaked introspection and Roy's chilling calm. The Roy sections are where Merriman earns his keep. That measured, almost gentle delivery for a character who is fundamentally monstrous? It's the right choice. It would've been easy to go broad and menacing, but the restraint makes it worse. In the best way.
My one knock: at this length, there are moments where the energy dips. Not Merriman's fault — even great actors can only do so much with passages that overstay their welcome.
Who Needs This and Who Should Run
If you're a Koontz devotee, this is apparently one of his better outings, and I can see why. The bones of the thriller are strong, and Roy Miro is a genuinely memorable villain. If you've read Mr. Murder, there's thematic connective tissue here.
If you scare easily, skip. If you don't, you need this — with caveats. The length is a commitment. The pacing is uneven. And the content gets dark in ways that aren't about jump scares but about the quiet horror of someone who's convinced themselves that cruelty is love.
Shirley (my cat) was unimpressed. I was unsettled for three days straight.
Check It Out, Don't Buy It Blind
This is a library rec, not a blind-buy rec. The good stuff is genuinely good — tense, creepy, well-performed. But at 24 hours with pacing issues, it's a lot to ask of a credit. Borrow it. Speed it up when you need to. And maybe don't listen to the Roy Miro chapters alone in the dark at 1 AM. (I did. I don't recommend it. I'm recommending it.)
