Esteban, a cheerful 12-year-old boy, lives in Barcelona, Spain. One day, he runs into Mendosa, a man who rescued Esteban from the Pacific Ocean twelve years ago. Mendosa tells him that the truth is that Esteban originally came from El Dorado, a mysterious golden city somewhere on a new continent. To find El Dorado, they set sail for the new continent.
During the voyage, Esteban makes two important friendships; Zia, a daughter of an oracle at Inca, and Tao, a descendant of the King of Mu, the mysterious civilization that sunk to the bottom of the Pacific Ocean. Three of them promised each other to find El Dorado, but there are many hardships waiting for them. According to a legend, there is a golden city beyond far west where the sun sets, and three youngsters will build a new world...