It was early July 2001 when Isabella Tree read an arresting headline in the foreign pages of a British newspaper: “NEPAL’S KING TURNS TO GIRL, AGED FOUR, AND HER MAGIC POWDER”. The news spurred her return several months later to Kathmandu, a city to which she had travelled regularly since the 1980s. Her return visit marked a turning point in a 13-year odyssey to uncover the truth about a little-known religious tradition involving a pre-pubescent girl, known as a Kumari, whom Nepalis regard as the embodiment of Devi, the universal goddess.

Tree had caught her first glimpse of a Kumari on her first visit to Kathmandu, in 1983, as an 18-year-old, when she and her gap-year travelling companions rented a couple of rooms in ‘Freak Street’, a fading hippie colony in the heart of the Nepali capital. The shutters of their rooms opened onto a square, in the far corner of which was the Kumari Chen, the palace where the Living Goddess lived in seclusion but for on rare occasions when devotees were permitted a brief audience. Fleeting glances of the young girl, about whom so many legends swirl, at one of the palace windows, captured Tree’s imagination, but it would be more than a decade before she was able to devote time to unravelling the mystery surrounding the child.

In The Living Goddess: A Journey into the Heart of Kathmandu, Tree deftly interlaces myth, religious belief, modern history and court gossip to tell the story of how the Kumari became so central to the rule of successive kings of Nepal, not only conferring on them legitimacy – by marking the forehead of a favoured incoming royal leader with a dab of sacred powder – but also acting as their divine protector. At the heart of her narrative are the terrible events that unfolded at the royal Narayanhiti Palace on the evening of

1 June 2001 when Crown Prince Dipendra went on a bloody rampage, shooting dead nine members of his family, including his parents and brother, before turning the gun on himself.

Amongst the many beliefs surrounding the Kumari is the assumption that the young girl temporarily enthroned as the Living Goddess only retains her divine power as long as she remains physically unblemished and shows no sign of blood loss, either through injury or through reaching puberty. Several weeks before the royal massacre in 2001, Tree heard from different sources that the Kumari at that time had developed a skin disease and then started menstruating, signalling that her power had dwindled and that she should have been replaced by another young girl, or Kumari-in-waiting.

Interwoven with these contemporary accounts of events leading up to and following the massacre is a historical explanation of how young Nepali girls, chosen as Kumari from a caste of Buddhist goldsmiths, came to be worshipped by a succession of autocratic Hindu rulers. It is a complex and fascinating tale, and Tree draws the reader in with her fine storytelling and eye for detail.

This is not a book for the faint of heart, outlining as it does some of the secret sacrificial rituals rumoured to surround the enthronement of a Kumari. These include the leading of the young girl along a white cloth through a courtyard where hours before the throats of goats and buffaloes have been pierced so that blood jetted out in gigantic fountains. This initiation is said to be carried out by tantric priests as a ritual of empowerment, with blood symbolising the energy of life – the reason custom demands the Kumari dress in red gowns with the jewellery and make-up of a bride rather than the white, yellow or saffron robes traditionally worn by priests, monks and ascetics.

But ultimately it is a book that highlights an appreciation of feminine divinity and spirituality that Tree concludes has been all but lost in Western society. “The closer I came to understanding the survival of the Goddess in Nepal,” she writes, “the more I became uncomfortably aware of her absence in my own culture and the entrenched androcentricity of almost every aspect of life into which I had been born.”

Christine Toomey is a journalist and the author of The Saffron Road: A Journey with Buddha’s Daughters, to be published by Portobello Books in June.