A darkly comic page-turner, My Sister, the Serial Killer by Nigerian author Oyinkan Braithwaite is one of the most talked-about novels of the year and was longlisted for the Booker Prize. It's a tale of two sisters – one an enabler, and the other in the middle of a killing spree – that subverts roman noir and sisterhood tropes. The New York Times calls it “a bombshell of a book – sharp, explosive, hilarious”. Oyinkan chats with Rebecca Harkins-Cross.