An exclusive black-tie birthday party. A sprawling mansion with a dark past. A body falling from a cliffside balcony onto the starlit outdoor dance floor. One of the guests is dead, and another is a killer - but who is the hunter and who is the prey? When social status is everything, and there is no price too high for adoration, there is no shortage of suspects: Was it Dani, the tenacious new mother with a history of postpartum psychosis, or Kim, the ex-wife with an alcohol problem? Orlaith, the elderly Irish nanny who talks to spirits? Mikayla, the lonely teenager, or the clique of toxic mean girls who pretend to embrace her? Or was it the pair of psychotherapists who watch and judge them all? And whose body is hurtling towards the pool?