Jani and the Greater Game by Eric Brown

Eighteen-year-old Janisha Chatterjee, the Cambridge-educated daughter of an Indian government minister, is coming home to visit her father on his death-bed, when her airship is attacked and wrecked. Amid the debris, a stranger-monstrous but kind-saves her life and entrusts her with a mysterious device, which pitches her head-first into the "Greater Game," the ongoing stand-off between British, Chinese and Russian powers in the Indian subcontinent.
Dodging British officers, Russian spies, and the dangerous priest Durga Das, Jani must bring the device to the foothills of the Himalayas; to the home of Annapurnite, the secret power source on which British domination was built. There she will learn the truth about Annapurnite-a truth that will change the world forever...