Florence Pugh is always a welcome presence on screen, capable of great performances in films that might not always be worthy of them. But when she finds herself in a film that can match her talents, as she does in Sebastián Lelio’s “The Wonder,” she’s a marvel.

Pugh announced herself in 2016 period drama “Lady Macbeth,” all steel and poise, a dominant presence capable of grabbing a film by the scruff of the neck and marching off with it. In the years since she’s put that ability to use in all manner of fare, from superhero flicks to horror movies to a certain hullabaloo alongside Harry Styles. Six years later, she’s back leading another period drama. The sang-froid remains, the same steel, but she’s a different actor now, capable of shouldering even more. In “The Wonder,” a film of considerable emotional depth that asks much of its actors, the result is perhaps her finest work to date.

Beautifully photographed by Ari Wenger, the cinematographer behind “Lady Macbeth” and “The Power of the Dog” captures the feverish tone of Lelio’s storytelling both figuratively and literally: Kafkaesque meetings with the committee stifling in their symmetry, while inside Anna’s dark attic room, warm candlelight picks up cold sweat on a young girl’s brow. The film’s ever quickening pulse comes courtesy of some tight editing from Kristina Hetherington as well as a score from Matthew Herbert, a composer whose roots in dance music remain evident here.