In 1920s Copenhagen, a woman named Dagmar Overbye was convicted of murdering multiple infants whose mothers had paid her to find adoptive families for them. She confessed to killing 16 babies, though the true number of victims was likely higher.

One of Denmark’s most notorious serial killers, Overbye is a character in the movie “The Girl with the Needle,” which arrives in some U.S. theaters Friday and is Denmark’s entry for the best international feature Oscar.

Yet the film isn’t a true-crime thriller, and Overbye isn’t portrayed as a straightforward villain. Instead the story is about “finding the humanity in these horrible deeds,” the film’s director, Magnus von Horn, said in a video interview — a tall task considering that the deeds involve burning, drowning and strangling babies.

How to perform the high-wire act of humanizing a killer? “You focus on the characters,” von Horn said. And you have to cast actors fearless enough to pull it off.

Enter Trine Dyrholm and Vic Carmen Sonne, the two leads in “The Girl with the Needle,” and two of Denmark’s most boundary-pushing actors.

The film — a social drama and dark fairy tale rolled into a black-and-white fever dream — follows Karoline (Sonne), a fictional character modeled after a real woman who became skeptical of Overbye’s adoption business.

Research into the court transcripts of Overbye’s trial informs the film, but it’s chiefly an imaginary retelling, with Dagmar (Dyrholm) depicted as both a survivor and a bringer of chaos. When Karoline nearly dies attempting to perform her own abortion in a public bathhouse, Dagmar intervenes and saves her life. The younger woman then volunteers to become a wet nurse for other newborns in Dagmar’s charge in exchange for room and board. Only later, after the two women have formed a bond, does Karoline discover the awful truth about what happens to the children.

“There’s no doubt Dagmar was a monster,” Dyrholm said. “But the movie is also about showing you her struggles and inner chaos.”

Dyrholm, 52, is one of Denmark’s most acclaimed actors, having won 10 Robert Awards — the Danish equivalent of an Oscar — throughout her decades-long career. She has achieved this stature by collaborating with provocative directors like Thomas Vinterberg and playing morally complex roles, such as a middle-aged woman who has a torrid affair with her teenage stepson in “Queen of Hearts” (2018).

“I’ve always fought to play women that certain directors or producers were afraid weren’t likable enough,” she said. “That’s something I like about the beginning of ‘The Girl with the Needle,’” she added, referring to the delirious opening sequence, in which phantasmal faces flash across the screen like images from a Rorschach test. “Within us are all these different masks, but some people, because of awful things that have happened to them, are forced to wear only one.”

After World War I, Denmark’s economy was in a slump, and single, working-class women were among the hardest hit. In the beginning of the film, Karoline moves into a leaky attic after she is kicked out of her apartment. When the owner of the textile factory where she works finds out she’s pregnant with his baby, his family forces him to abandon — then fire — her.

We empathize with Karoline’s struggles, yet she’s also callous, an embittered product of her social reality. When her husband, whom she believed to be dead, returns home from the war with PTSD and a disfigured face, she violently tosses him out of her home.