You’ve got a plot that was clever enough to land veteran character actress Veronica Cartwright (“Sideways,” “Alien,” “The Birds”).

Shooting and editing your film, you can’t wait to get to the third act where you can “explain” its cleverness to death.

And then you kind of give away the game by titling your picture “The Ruse,” implying that things are not at all what they seem. Clever.

Writer, director, producer and editor Steven Mena’s latest is a tepid, sleepwalking tale of a home health care nurse (Madelyn Dundon) stuck in a not-that-spooky lakeside house with a haughty, demented and ill-tempered retired orchestra conductor (Cartwright) who is sure her late husband Albert “visits” her.

Was Albert behind the previous nurse’s (Kayleigh Ruller) disappearance? What we’ve seen in the opening scene suggests as much.

But even though Nurse Tracy vanished without quitting or even saying goodbye, Nurse Dale needs the “second chance” this ordeal-of-a-job promises. She’s ever so eager to get back to work after something unfortunate happened on her last assignment.

Her controlling live-in boyfriend (Drew Moerlein) disapproves. She’s ogled by the delivery guy (T.C. Carter) who tries a tad too hard every time he shows up with food or whatever at the remote home in rural Maine. Then there’s this single-dad neighbor, Tom (Michael Steger), who shows up at the darnedest times — in the middle of a blackout thunder storm, for instance — to “just see if you needed help.”

His little girl (Nicola Jeanette Silber) is the only blunt, cards-on-the-table character in this world.

“I give you three days, tops,” she chirps. The place is “haunted,” she insists. She’s seen the “ghost.” And when she leaves, she doesn’t tell Dale “Good bye.”

“Nice knowing you” is the best line in the script.

Cartwright is in fine form as an invalid who boasts of her full life, insults Dale’s underachieving (by comparison) 28 years and has been labeled “OCD” by an earlier nurse, in addition to her respiratory and dementia problems.

But she’s not scary by herself. And this movie slow walks its away through no real jolts at all before backing into a third act built around a rural Maine cop (Michael Bakkensen) who is a regular Sherlock Holmes at leaping to the wrong conclusion, leaping again and tumbling into some solution that he insists the police are entirely too clever to “miss.”

Writer/director Mena (“Bereavement,” “Brutal Massacre: A Comedy”) has made half a dozen films now, and a few people might actually see this one, as it stars Ms. Cartwright.

The production values are good even if the performances surrounding Cartwright are a tad tentative, low-heat and low-energy. And as he edited this, the funereal pacing is on him, too.

Still, if your thriller’s quick enough and cryptic enough, viewers won’t notice it’s not remotely as clever as you thought it was. But when you title your ghost story “The Ruse,” you’ve already given away that.

Rating: R, violence

Cast: Veronica Cartwright, Madelyn Dundon, Michael Steger, Drew Moerlein, Kayleigh Ruller and T.C. Carter

Credits: Scripted and directed by Stevan Mena. A Seismic release.

Running time: 1:40