The title of Oyinkan Braithwaite’s debut novel, “My Sister, the Serial Killer,” is simultaneously accurate and misleading. The book is indeed about a serial killer and her sibling, but it is not at all the pulpy slasher story you might expect. Instead, it is a playful yet affecting examination of sibling rivalry, the legacy of abuse and the shallow sexism of Nigeria’s patriarchal society.

Our narrator, Korede, is a nurse at a hospital in Lagos. She is homely, dutiful and lonely. She carries a torch for a doctor named Tade, but her feelings are not reciprocated. Korede’s sole confidant is a man in a coma, to whom she unburdens herself like a patient to a shrink. Most of those confidences have to do with Korede’s younger sister, the beautiful but reckless Ayoola, who has an unfortunate habit of killing her boyfriends.

At the opening of the novel, Ayoola has just murdered her third victim, the unsuspecting Femi, with a knife. “The knife was for her protection,” we’re told. She carries it in her purse “the way other women carry tampons.”

Ayoola summons Korede, who races over to clean up the crime scene and dispose of the body. Korede is both enabler and accomplice to her sister’s homicidal habit and is seemingly powerless to stop it.

There are complications. The police discover a bloody napkin at Femi’s home; a witness comes forward. Then Korede’s doctor crush, Tade, meets Ayoola and falls under her spell. Will he become her next victim? Finally, the coma patient wakes up and tells Korede that he remembers everything. What is she to do?

Braithwaite generates a lot of humor out of the disparity between Korede’s and Ayoola’s appearances: Ayoola has “a figure eight — like a Coca-Cola bottle” and Korede has “a figure one — like a stick.” Ayoola gets flowers and vacation invitations from wealthy men while Korede is told, “You’re going to make someone an awesome wife.” But the novel wants to do more than dramatize the privilege enjoyed by Ayoola because of her looks.

Whatever resentment Korede feels toward her sister, there is a deep and enduring bond between them. They live with their widowed mother in a mansion built by their abusive, philandering father. The reader comes to see that his legacy of violence and betrayal is at the root of Ayoola’s murderous spree. (It is the father’s knife that Ayoola carries in her purse.)

As the novel moves toward its twisty, satisfying denouement, we learn that Korede can be just as ruthless as her sister. In its darkly comic depiction of two women teaming up against the powerful, abusive men in their lives, “My Sister the Serial Killer” feels like an ideal book for the present moment.

Jon Michaud is the author of the novel “When Tito Loved Clara.”


By Oyinkan Braithwaite

Doubleday. 240 pp. $22.95.