It all begins when Grandpa Yólotl disappears. Matías, Claudio, Pato, Katy and loyal dog Duke uncover signs that will lead them to a great adventure, facing unimaginable creatures, astonishing characters - that once belonged to an ancient civilization, and a couple of rogue treasure hunters. The promise of their grandfather is the force that will guide these heroes, ready for anything, provided they always stay together and discover the secret of the jade medallion.