I thought at best it would rekindle my nostalgia for stalker thrillers from the 1990’s. The commercials for Greta, about a young single woman (Chloe Grace Moretz) who befriends an old woman (Isabelle Huppert) who turns out to be a crazy clingy stalker, looks competent but soft-edged and formulaic – but I’m talking commercial judging here. While it goes through the familiar motions for half its running time, it takes on some surprises. There is a dream sequence that intersects with a drug-induced hallucination, and we’re unsure what is the true reality, and I’d be in denial if I didn’t confess it messed with my head. Director Neil Jordan, who seems knowing of the thriller clichés, subverts those clichés and takes some hard left turns. I held on quite fixed in my seat for the last half.

Sure, Jordan falls onto the crutch of reusing some of those clichés, such in a sequence where crazy Greta takes text message photos of an unwitting subject going long without being detected, but you might yourself like me kicking yourself just to go with it. Jordan coaxes quality performances out of Huppert and Moretz, which is easy enough to do but I still imagine most directors would fail to get us to care about their woes first.

I’ve seen Moretz for many films in her young career of getting dragged through high concept flicks and silenced throughout loud special effects extravaganzas. A movie like “Greta,” no matter its trappings, at least allows her to show a wider emotional range, vulnerable but capable, a tad gullible but mature, than we’re used to. She’s a sad puppy who lost her mother some time ago and opens herself to be a friend to a wise old soul, but she barked up the wrong tree.

How crazy does things get? I’ve seen the scenario dozens and dozens of times before, if not hundreds, and yet I was a little freaked out. Huppert has the overcaring mother look in her eye that’s intense enough that she looks like she could kill doing it. Maybe “Greta” is trash, but it’s the kind of fearless trash that does give you more than you bargained for, no matter how much you think you know the genre.

Maika Monroe plays Moretz’s roommate and Colm Feore plays the father.

99 Minutes. Rated R.

STALKER THRILLER / MATURE TEENS / DARK ROOM CHILLS

Film Cousins: “Single White Female” (1992); “The Piano Teacher” (2001, France); “The Gift” (2014); “Room” (2015).