Emily Tempest is appointed an aboriginal community police officer for the Moonlight Downs station. Investigating the possible murder of an elderly geologist, she encounters Danny, an emotionally fragile Stonehouse mob teenager who is traumatized by the image of "poison flowing green." The terrain of Australia, a Japanese rock garden painter, a rash of unexplained illnesses, and the implausibility of two elderly friends killing each other present Emily with a unique puzzle.