My Sister, The Serial Killer is a scorching crime thriller

What do you do when your sister calls you one night to say she's killed a man? You help her move the body, of course. And don't forget the bleach. "Ayoola summons me with these words - 'Korede, I killed him'. I had hoped I would never hear those words again." This is how Oyinkan Braithwaite's debut novel, set in Lagos Nigeria, opens up.

The two sisters couldn't be more different: Ayoola is a glamorous fashion designer with a huge Instagram and Snapchat following (not to mention all the men vying for her attention), while Korede is a pragmatic and dependable nurse. Korede also happens to be a compulsive cleaner, which is lucky for Ayoola, who kills all her lovers. "Femi makes three you know. Three and they label you a serial killer."

It seems that Korede is resigned to her fate as her sister's protector, until Ayoola starts flirting with a handsome doctor at the hospital where Korede works. The doctor happens to be the love of Korede's life, which puts her in an impossible situation: should she stay loyal to her sister or protect the man she loves?

Braithwaite is a freelance writer and editor, a graduate of Creative Writing and Law from Kingston University, and was shortlisted for the Commonwealth Short Story Prize in 2016. She is also an acclaimed spoken-word artist. Her propensity for poetry shines through in her debut: from the stark, hard-hitting prose to the careful arrangement of each chapter around a specific theme, with evocative titles such as "Bleach", "Knife", "Wound" and "Father".

At first glance, the story may come across as deceptively simple, but My Sister, the Serial Killer is so much more than a crime thriller. As the story unfolds, we learn that the sisters and their mother live alone in a mansion in Lagos. Through stolen glimpses of memory here and there, we come to learn that their father ruled the household with a sharp tongue and a cane.

Trauma and abuse permeate the book, yet the nuanced storytelling doesn't allow for easy conclusions - you can speculate that the killings are Ayoola's way of seeking revenge on her father, but you can just as easily deduce that she's a killer who loves killing.

There's also the real possibility - and that's the beauty of this layered novel - that she committed the murders in self-defence.

The novel plays inside the realms of domestic noir, a subgenre of crime fiction that was first coined by novelist Julia Crouch: "Domestic noir takes place primarily in homes and workplaces, concerns itself largely (but not exclusively) with the female experience, is based around relationships and takes as its base a broadly feminist view that the domestic sphere is a challenging and sometimes dangerous prospect for its inhabitants."

My Sister, the Serial Killer is a story of relationships: the bond between two sisters forged through childhood trauma; their relationship with their father (abuser) and mother (survivor); and Ayoola's precarious relationships with men - whether young and handsome or old and rich.

Despite the dark subject matter, the novel never feels heavy. The narrator's matter-of-fact descriptions of how to clean up blood and move a dead body are vivid and shockingly hilarious, and each carefully crafted sentence cuts to the bone.

My Sister, the Serial Killer is scorching. I can't wait for Braithwaite's next book.

• Our reviewer, Anna Stroud, gave 'My Sister, The Serial Killer' 5/5 stars.