Director Paul Feig has put a feminine twist on gritty noir tropes in “A Simple Favor,” injecting the film with dark humor and sets that bend reality to bring the film’s two antiheroines to life.

The film opens with Stephanie Ward, played by Anna Kendrick, livestreaming on her vlog, which she uses to offer tips and tricks to other mothers. However, Stephanie’s comfortable, suburban life is upended when she strikes up a complicated friendship with Emily Nelson, played by Blake Lively, who goes missing after asking Stephanie for a simple favor — to pick up her son after school.

Emily is declared dead after her body turns up on the shore of a lake, which pushes Stephanie to fill the gap she has left behind. Stephanie kindles a relationship with Emily’s husband, moves into her house and cares for Emily’s son as she cares for her own.

Now, I know what you’re thinking — I just threw those last few plot points at you without much context or elaboration. Well, that’s sort of what the film does too.

“A Simple Favor” grazes over the backstories of its main characters with a series of choppy flashbacks to detach their pasts from the present. Moments like these are used to prolong the suspense, detracting from the important ways these events have fundamentally shaped the characters. Obscuring these storylines works against the film’s larger goal — to encourage the audience to become invested in uncovering these characters’ personal mysteries.

Despite this setback, some parts of the movie have standout potential. Feig manages to successfully navigate the play between truth and fiction: There were points in the film where I felt myself actively questioning if what was unfolding onscreen was real, or if it was a figment of a character’s imagination. This effect was induced by the combination of the way the film is shot, with long, symmetrical takes that make certain scenes feel dreamlike, and the way it is set — relying on minimalistic, modernized sets and excessive color coordination to create an eerily staged atmosphere, reminiscent of a film like Frank Oz’s “Stepford Wives.”

This surreal atmosphere is bolstered by Stephanie’s vlogs. In one scene, she informs her viewers of Emily’s disappearance, actively drawing her audience into the “reality” she is experiencing, so they can relate to her at a more profound level.

Yet, her platform is a clever ploy. Contrary to the purpose of a vlog, which is often used to convey transparency, the details that underly the film’s plot are mostly hidden, only uncovered toward the end.

“A Simple Favor” touches on a new subgenre. Feig bridges the disillusioned, dark, sometimes gritty nature of a noir film with the flashy delicacy of strained femininity. He incorporates common noir tropes, like the femme fatale, convoluted storylines and themes of corruption and misguidance. But these qualities are infused with witty, unconventional banter, dark humor and the guise of two well put-together women who slowly come undone as the film takes form.

This fusion of noir elements with a refreshing embodiment of the antiheroine — through not one, but two complex women — means that “A Simple Favor” does not live within any pre-existing cinematic framework. It is difficult not to become absorbed with Stephanie and Emily’s relationship as the two characters blossom independently onscreen.

As the plot thickens and the characters’ facades fall back to reveal their maniacal schemes, Stephanie attempts to shape herself to Emily’s mold, while still clinging to the safety of her organized, domestic life. But in contrast to the main characters’ difficulties to mediate their internal struggles, the film strikes a sleek balance between what is dark and what is chic.

Blending notes of Hitchcock with twisting narratives, “A Simple Favor” taps lightly into a new subgenre: a glossy, seductive version of noir. Despite the weakness of the flashback scenes, the film offers up a delightful plate of twists and turns — from the casting choices to Feig’s decision to take his humor down a dark, winding road. In “A Simple Favor,” Feig has unveiled something beautiful, something polished and dark.