"I have always been drawn to dark topics," says Oyinkan Braithwaite, the 30-year-old Nigerian author behind the critical darling of a novel My Sister, the Serial Killer.

Her declaration helps explain the subject and title of her debut novel, which tells the story of Ayoola, a young woman who has developed a not-so-healthy habit of murdering her boyfriends, leaving her older sister, the book's protagonist, Korede to clean up her mess. You may have noticed it's ubiquitous cover—which features a young black woman wearing a headwrap, casually looking on as a knife-wielding hands is reflected in her sunglasses—on your timeline or at your local store. The internationally-released, Nigerian-made novel sits confidently on retail shelves previously reserved for mass-market thrillers.

The dark and humorous, Lagos-set novel is extreme—but not just because of all the murdering that happens. It also examines the extreme nature of the many things that can push people to the edge. For the sisters, it's: intergenerational trauma, abuse, the prevalence of a culture that rewards beauty above all else, as well as having to battle with their own personal shortcomings—just to name a few.