In the literature of Tibetan exile, horrific and heart-wrenching accounts of torture in Chinese prisons, of treacherous escapes to India, and of a natural and religious landscape decimated by the communist invasion are sadly the norm. "Born in Tibet," by Chogyam Trungpa Rinpoche, "The Autobiography of a Tibetan Monk" by Palden Gyatso, and "Freedom in Exile: The Autobiography of the Dalai Lama" echo the ordeals of thousands of others, standing in for the 1.25 million Tibetans who have died as a result of the Chinese takeover 40 years ago.

It is rare, however, to hear a woman's account, and rarer still to find an exile's story like "Sorrow Mountain: The Journey of a Tibetan Warrior Nun" (Kodansha America, 324 pp.), which is told with the detail and nuance, if not the stylistic intimacy, of a novel. The storyteller Ani Pachen, a Buddhist nun who was once the leader of a bona fide tribe of warriors, a Tibetan freedom fighter and throughout, a Buddhist of unshakeable conviction. Her odyssey, as told to Adelaide Donnelley, ranges from the splendors of old Tibet to the cruel reality of occupation, and shines with an unwavering glimmer of hope.

The daughter of a powerful local chieftain in Kham, in the great, wild expanses of eastern Tibet, Ani Pachen rode horses and learned to shoot from an early age, camped with nomadic herders in the summer, and lived in a household where every day, hundreds of guests gathered, waiting for their disputes to be settled by her father. Pachen exhibited a special spiritual sensitivity and studied the Buddha's teachings with such ardor that when her father arranged her marriage, to the son of an allied chieftain, she ran away from home rather than risk losing a chance to be ordained and devote her life to practicing the Dharma. "Marriage is suffering," a devout aunt told her. "The path is full of sorrow."

But Pachen came to know suffering of a different order. In the late 1950s, soon after her 21st birthday, the Chinese invasion thundered through her country and breathless messengers reported humiliations, beatings, work camps, and the bombing of monasteries. When Pachen's father died (of a heart "broken" for Tibet), leaving her in charge of the family and the freedom fighters he commanded, she became overnight one of the few female leaders of the resistance movement. Within the year, though, she, her family, and hundreds of her kinsmen and neighbors were captured and imprisoned.

Pachen spent the next 21 years in Chinese work camps, enduring relentless torture, forced labor, and near starvation. But her familial legacy of grit and defiance, and her fierce devotion kept her alive. Faced with nine months in solitary confinement, locked in a dugout the size of a coffin, she dedicated herself to completing 100,000 prostrations. Ultimately, she escaped to India, where she met the Dalai Lama, whose image had sustained her in her darkest moments.

Some of the book's most evocative passages are not descriptions of Pachen's years in prison (where almost daily struggle sessions "left the floor black with my hair"), or of her harrowing escape, in tattered cloth shoes, over the Himalayas to India, but of her early life as a young chieftainess, when Tibet was still shut off from the rest of the world. As the Chinese moved into Tibet, Pachen sees flying overhead a "machine with wings like a bird, that filled the air with thunder." The first electric light she sees is a bare bulb hanging from the ceiling of an interrogation room.

Wonderful images of Tibet's traditions, (before the Chinese banned them) abound. Of the family's preparations for Losar, Tibetan New Year, she remembers, "the coverings on the doors and windows were changed. Altars were decked in dried barley, with a sheep's head and rice set to one side. Fresh silk was put around the statues of each deity, and pillars were wrapped in brocade. New mattresses and rugs were brought to the kitchen for guests. Even the good luck symbols on the walls were given a fresh coat of white paint." On the eve of her flight into the hills, before the Chinese reached her village, Pachen organizes a caravan of hundreds and packs up her family's possessions, wealth measured not in stocks and nice cars, but ornate jewelry and healthy livestock. Throughout the book, Pachen quotes from her lamas, and buoyed by their teachings on impermanence: "The nature of mind is clear light, and our experience in the world only passing waves on its surface," her teacher Gyalsey Rinpoche told her, and it echoed each time a relative starved to death, or a friend was dragged off to the execution block. Like a beacon, visualizations of the Dalai Lama trained her mind on a freedom that transcends prison walls, and kept her morality intact: Pachen was known for infuriating her Chinese captors by refusing to identify resistance fighters or to rat on other prisoners. For all the book's pathos, "Sorrow Mountain" is rather simply told. Adelaide Donnelley composed the book from hundreds of hours of conversations with Pachen at her monastery in Dharamsala. At points, the dialogue sounds stilted, but with elegant imagery, and an unbeatable story, Donnelley interprets Pachen's extraordinary life and shows, in ordinary detail, how the Chinese government has tried and failed to destroy the heart of Tibet.