In this group of wealthy, mysterious friends, she has your back...and may stab you in it. Pampered Susan is living the perfect life in leafy Kingston, London, but she'll never let anyone see the darkness she's concealing behind the diamonds and rosé. Grace is new to the group, seemingly the perfect wife and mom, yet no one knows what's happening behind closed doors. Loner Natalie hides the pain of her childhood behind a carefully ordered life, but how long can the past stay hidden? These three unlikely friends are brought together for a weekly class run by a beautiful, friendly instructor, Jade. But when Jade goes missing under mysterious circumstances, the group starts to unravel. And as their darkest secrets come to light, it seems that no one can be trusted...even their closest friends.