His soul now walks the paths of the spirit world, carried by the winds, far removed from all earthly splendor. Yellow Wolf. Towards the end of the 19th century, Perla Ruiz-Tenguillo traverses the southern part of North America at the head of a small group of adventurers. Their goal: to wander in the footsteps of her ancestor, Hernan Ruiz-Tenguillo. For the invisible world revered by the Indians and described by her ancestor two centuries earlier still exists! Only now it remains hidden from the eyes of the white people, so they do not seize its magical powers. Perla hopes to rediscover this universe. But for that, she must cross the ultimate boundary - that of reality...