In which a young adventurer finds himself amidst the fierce Black Tatars of Thibet and joins their siege against the city of Yarkand, employing wondrous electrical devices to shift the tide of battle and reclaim stolen treasures. Amidst clashes and cunning stratagems, he navigates alliances and enmities in a strange land, ultimately taking flight upon a marvel of invention that whisks him away from the fray.