My Sister, the Serial Killer

Begins quickly with big sister Korede (the narrator) helping her little sister Ayoola deal with a dead body. Ayoola says her boyfriend attacked her although Ayoola has no marks or bruises and her boyfriend has her knife in his back. And, as Korede notes, he's the third one. Told in simple language and set in Nigeria (where the author is from) this story zips along super fast and it's a fun read.