Welcome to Aberfal Boys High School. Independent jewel of academic and sporting excellence in the South-west - until the headmaster is murdered in his study. And now the Year Seven School Mums' WhatsApp Group really do have something to talk about. As the resulting police investigation reveals more and more of Aberfal's long-hidden secrets the list of suspects who wanted the headmaster dead grows by the day. And far from being a glittering jewel of exclusivity and excellence, it would appear Aberfal Boys High School is rotten to its core.