At first glance, “Before I Fall” looks like an easy target: It’s typical young adult territory, a high-school flick in angst-ridden mode, and a rip-off of “Groundhog Day.”

People who review movies based on subject matter will have a field day with this. If you believe movies actually need to be watched, however, you might find yourself sucked in.

It takes a while: Because I didn’t know anything about this movie’s structure, I was completely puzzled by the opening 20-plus minutes.

We meet Sam (Zoey Deutch), who goes through a day with her posse at school, culminating in a big party at night.

Sam and her shallow friends (Halston Sage, Medalion Rahimi, Cynthy Wu) casually exploit their position of dominance. They’re especially cruel to a misfit classmate (Elena Kampouris).

Surely we’re not meant to take these privileged mean girls as heroic, are we? As I wrote in my notebook while watching the movie, “Are these four supposed to be horrible?”

Suddenly, at the end of the day, the girls are in a car accident. The screen goes black.

Then the film’s design kicks in: Sam wakes up again, about to re-live the same day. And then live it again. And then — well, you’ve seen “Groundhog Day.”

In a way, the theme (based on Lauren Oliver’s novel) is essentially the same one we saw in the Bill Murray movie. Sam won’t be released from the cycle of days until she becomes a better person.

What makes this formula work is the intensity director Ry Russo-Young brings to it. “Before I Fall” is drenched in atmosphere, whether it’s the damp mood of a Pacific Northwest suburb or the hothouse of a teen party.

The film has a good cast, but especially benefits from an excellent performance by Zoey Deutch, who made a strong impression in “Everybody Wants Some!!” She’s the daughter of Lea Thompson (and Thompson’s “Some Kind of Wonderful” director Howard Deutch), but she has a gravity all her own.

Deutch does something delicate here: For most of the movie, she’s involved in the action but also standing apart from it, watching the day unfold yet again. Each day the same, except for tiny variations.

If you strip away the supernatural element, that could be a description of high school. Maybe that’s another reason this movie carries unexpected weight, and qualifies as a pleasant surprise.

“Before I Fall” (3 stars)

“Groundhog Day” in high school, as a teen (excellent Zoey Deutch) re-lives the same day over and over again. This angst-ridden young adult premise shouldn’t work, but it’s strong on atmosphere and builds up a real gravity as it goes along.

Rating: PG-13, for language, subject matter

Showing: Alderwood Mall, Everett Stadium, Galaxy Monroe, Marysville, Oak Tree, Sundance Cinemas Seattle, Woodinville, Cascade Mall