When Claire Fleetwood, a young American forensic photographer, inherits a large house and garden in London's East End from relatives she never knew she had, she imagines it will be a slice of the English dream. But after the brutal murder of her best friend Sally Rivers, Claire learns that her inheritance involves more than she wanted or bargained for. Claire joins a scientific expedition led by her cousin Jack Ironstone, one of the men she suspects of being responsible for Sally's murder. Her journey leads from Jack the Ripper's Whitechapel to the Fleetwoods' murky roots in India's opium trade and the wild 'paradise' valleys of Tibet. It parallels a route taken during Britain's great 19th-century triangulation of the Himalayas by Claire's distant relative Magda Ironstone and a mysterious Indian botanist. As Claire reconstructs a triangular love affair she imagines took place, the contemporary story is overtaken to deadly effect by Magda's.