A daring young American nicknamed Headlong returns to a volatile border town and becomes embroiled in a quest prompted by a veiled woman's arrival and rumors of ancient treasure. He and a disparate band cross into dangerous terrain to pursue relics tied to the region's precolonial past, confronting rival claimants, betrayals, kidnappings, and narrow escapes in cliff lairs, mirrored labyrinths, and ruined gardens. The expedition forces shifts in command, exposes hidden motives and deceptions, and develops a charged romantic entanglement that forces characters to choose between honor, loyalty, and personal desire.