Nat Spiller, an admired climate change activist, accidentally drowns. An accident? His partner Ellie thinks otherwise. Pam, Ellie's aunt, draws a reluctant Lauren Fraser into the mystery. The formidable Spiller clan tell Lauren to butt out. Will they follow through on their threats? As Lauren investigates, suspects multiply. Was it Harold the bird-watcher, envious of Nat's charisma? Or Derek, whose shonky Antarctic climate science Nat was about to expose? Or Rodger, wanting Ellie for himself? Lauren enlists her circle of friends to help build the evidence for murder. The truth catches them all unawares.