If “Gone” were a single episode of a police drama — which is what it feels like it is, albeit a very stupid one — I would have been interested enough to keep one eye on the TV while I folded laundry. The scenario is intriguing in the way that the average “Law & Order: SVU” scenario is intriguing, and I’d have been curious to see how it would turn out. And then, when it was over, I’d have been disappointed by the anti-climactic conclusion and the general idiocy of the last act. Maybe I would have thrown something at the TV.

That’s if “Gone” were a one-hour TV show! It’s even worse as a 94-minute movie, because you have to leave your house and pay money to watch it. This is not something that’s worth paying for. No money should ever change hands in any “Gone”-related interaction, unless it is because you are buying matches and gasoline to set all the copies of it on fire.

This unthrilling thriller stars Amanda Seyfried as Jill, a bug-eyed young Portland woman whose college-student sister, Molly (Emily Wickersham), goes missing on the morning of a big test, leading Jill to conclude that Molly has been kidnapped. This conclusion does make some sense, mind you. Jill herself was abducted a year ago, barely escaping with her life, and has feared ever since that the perpetrator would return to finish the job. The cops never caught the guy, you see, on account of they don’t think he exists. They couldn’t find any evidence that any crime had been committed. Jill might be a nut who conjured the whole thing in her imagination.

The police are not much help today when Jill barges into the precinct, all bug-eyed and panicky, declaring her sister missing. Even if Jill’s story from a year ago is true, there’s no reason to think the guy has come back. For that matter, there’s no reason to think Molly is even “missing.” She’s an adult, after all, and adults do sometimes leave without telling their sisters where they’re going. I can assure you, if Jill were my sister, she would NEVER know where I am.

The main cop, Det. Daniel Sunjata from “Rescue Me,” is the most dismissive of Jill’s hysteria, while a new guy, Det. Wes Bentley from “American Beauty,” thinks she might be right. Det. Daniel Sunjata explains to Det. Wes Bentley (and us) what Jill’s whole backstory is. Now we’re wondering too: Is Molly really missing? Did the same guy take her? Or is Jill insane? How much, if any, of this is only happening inside her bug-eyed head? What’s up with those pills she has to take every few hours? Are they to help her eyes stay bugged out?

Left to her own devices, Jill becomes an amateur sleuth, using what scant clues she can find to track her sister’s whereabouts, all while driving around Portland like a maniac as the cops try to calm her down. The movie may be dumb, but Jill isn’t, at least not for the first hour. She cleverly deduces several things that weren’t obvious, and she thinks quickly on her feet. It’s only in the final 30 minutes that she turns into a complete moron, allowing herself to be led via cellphone into a dangerous situation that she has no reason to believe will help her find her sister.

Like the episode of “Law & Order: SVU” that I’d rather have been watching, “Gone” (the first English-language film by Brazil’s Heitor Dhalia) pads out its running time with the requisite false suspects, sidetracks, detours, and red herrings. Problem is, they don’t add up to anything. When all is revealed at the end of Allison Burnett’s ludicrous, dimwitted screenplay, the only normal reaction is: “That’s it?” This could be followed by a series of reactions each beginning with “Wait, but why did…” or “Wait, but who was…” or “Wait, but what about…?” I would recommend seeing this film only if you like wasting your time and money on terrible things. Even then, I would think twice.

D- (1 hr., 34 min.; PG-13, one F-word, a little violence, some grisly images.)