"When a high-pitched scream perforated my peace at the National Botanic Gardens in Dublin it seemed that it was not only audible but almost visible. It was as though the sound had made the light there vibrate - as though the plants and trees were altered by it." Court stenographer Beatrice Barrington is at the National Botanic Gardens, Dublin, when a woman runs screaming from the Palm House. A man has plunged from the high walkway inside onto the flagstone floor below. He's identified as gardener Paddy Hogan. An accident? Or could it be suicide? Examining the scene, Beatrice believes neither is likely. She begins to suspect Paddy has been murdered, though the local gardaí seem to believe otherwise. Paddy's sister Ava begs her to find the truth about his death and, though Beatrice has promised herself not to get involved and has been warned off by Detective Inspector Rebecca Maguire, she agrees. And when her former lover, ex-detective Gabriel Ingram, returns from a long recuperation in Donegal, together they get drawn into the case. Investigating the lives of staff and visitors at the gardens, they uncover lies and deception but a motive for murder remains elusive . . .