Wellingtonian Lauren Fraser is in Melbourne when she hears that Nat Spiller, an admired environmental activist, has accidentally drowned. That’s the police verdict. But was it an accident? Her friend Pam’s niece Ellie, Nat’s partner, thinks otherwise. The Spiller clan, property developers, don’t want any fuss, but Lauren reluctantly agrees to investigate for Ellie. Suspects begin multiplying. Was it Harold, the bird-watcher who was jealous of Nat? Or Derek, whose shonky climate science Nat was about to expose? Or Rodger, obsessed with Ellie? Lauren enlists Pam and her friend Ro to help, with Ro extending her watchfulness down to Scott Base in the Antarctic. Evidence gradually builds up, but the truth is shocking.