A paranormal investigator. A bunch of unsolved cases. What you hear will give you chills.

Lock the doors, turn off the lights, and put on your headphones. It’s time to discover The Black Tapes, a weekly (fictional) podcast that’s far more unsettling than it has any right to be. The first season, which wrapped up last week, numbers 12 episodes, each around 40 minutes long. It’s perfect for binge-listening—I managed to devour them all in a day.

Framed as a spinoff of Pacific Northwest Stories, an alternate-universe This American Life, the podcast begins as a profile of Richard Strand, a world-renowned paranormal skeptic and investigator (a James Randi type). But it evolves into something else when host Alex Reagan discovers Strand’s backlog of unsolved cases, the so-called “black tapes,” and joins him in reinvestigating them.

These mysterious phenomena include a shadowy figure that haunts the margins of a family’s photographs and a mute teenager seemingly capable of teleportation. I don’t want to give much away, but over the course of the season, it becomes clear that Strand’s black tapes have more in common than anyone would expect—and that there’s more to the man himself than meets the eye.

The Black Tapes released its first episode in May, then launched a successful Kickstarter campaign in June. It has a devoted subreddit with nearly 1,000 members. Last week, production company Minnow Beats Whale launched an in-universe spinoff, Tanis, which (along with The Black Tapes) has already cracked the top 25 podcasts on iTunes.

What separates The Black Tapes from, say, a Welcome to Night Vale is its commitment to realism. The series is a pitch-perfect imitation of Serial, right down to the Nick Thorburn-style theme music, the frequently quirky interview subjects, and the way the host playfully reminds you that this is a story told week by week, so catch up if you need to; she’ll still be here when you get back. That’s what makes this show so effective: once you let your guard down and become absorbed by the familiar atmosphere, it’s all the more frightening when the narrative deviates into the realm of the supernatural.

There are no jump scares here, just thoughtful, finely drawn characters. In the same way that the scariest horror movies are often those that rely the least on visual effects, The Black Tapes is perfectly suited to the podcast medium—there’s no world more immersive, or more chilling, than the one you’ve constructed in your own mind.

Molly Fitzpatrick is senior editor of Fusion’s Pop & Culture section. Her interests include movies about movies, TV shows about TV shows, and movies about TV shows, but not so much TV shows about movies.