Good thrillers make you work to figure out what’s going on and assume you’re smart enough to do just that.

Bad thrillers explain, explain and over-explain, as if you’re even dumber than the folks who made them.

“Paranormal Prison” has a great location — a closed penitentiary in Boise, Idaho. It’s got a time-tested concept, a paranormal Youtube show comes in to “Blair Witch”/reality TV the place one last time before it’s torn down.

But half of its paltry 70 minutes of screen time are spent “explaining.”

There’s “scientist” Sarah (Paris Warner, who looks like a college freshman), who explains her imaginary ghost detecting gear, ad nauseum, as the episode of the show, “The Skeptic and the Scientist.” unfolds. The sound mixer Ashley (Corynn Treadwell) explains the origins of her thoughts about the supernatural, stemming from her time in combat. Sarah explains her own connection to the subject.

A tour guide for the prison, a retired guard (Easton Lay) explains the history of the place, explains why they “don’t want to be in here after dark” because “there’s no lighting.” When there is, and that’s plainly the whole point of the show’s visit to the place.

And in the third act, after an hour of failing to deliver frights, we’re treated to flashbacks “explaining” the logic of what this or that character from earlier remembers (as do we), spoon-feeding us earlier scenes that might help get them out of a perilous situation.

Trust fund doofus Matthew (Todd Haberkorn) is director and star “skeptic” of the show, quick to dismiss anything they run into as this guard walks them through the cell blocks, Death Row, solitary (“‘Siberia,’ everybody called it.”), the deathly-dangerous laundry room and the Death House, with its “hang and drop” room.

Those four roses blooming out-of-season outside? They’re connected to the legend of a racist serial killer suffragette (Only in Idaho, right?) who haunts the place. You smell roses? You’re in trouble. If a rose in that bush outside goes missing, watch out.

So naturally somebody has to say “I smell roses.” It’s as inevitable a line as “It’s awfully quiet in here.”

The script plays as “typed” more than written. The line-readings sound like just that — readings, flatly intoned by a cast not quite up to acting on camera. Yet.

And the “frights” cooked up by director Brian Jagger? Not worthy of the name.

My advice? Don’t do the crime — streaming this — if you can’t do 70 minutes of hard time.

MPA Rating: unrated, seriously tame

Cast: Paris Warner, Corynn Treadwell, Todd Haberkorn, Easton Lay and Brian Telestai

Credits: Directed by Brian Jagger, script by Brian Jagger, Randall Reese. A Gravitas Ventures release.

Running time: 1:11