In the year 1532, Esteban, a twelve-year-old orphan from Barcelona, possesses the strange ability to command the Sun to appear, earning him the title "Child of the Sun." After his adoptive father dies, Esteban learns that he was rescued as a baby from a sinking ship at sea. The mysterious medallion he has always worn leads to a trace somewhere in the New World, likely originating from the legendary Cities of Gold. Esteban leaves Spain to search for his parents and discover his true identity. Along the way, he meets Zia, an Inca girl who was kidnapped from her people years ago and wears a medallion exactly like his. Later, they are joined by Tao, a young castaway from the Galapagos and the last descendant of the Empire of Heva, which is said to have built the Cities of Gold. Following Coyolite—the shining star depicted on their medallions—the three children travel through the unexplored New World, seeking the Cities of Gold and believing that this path will lead them to their lost parents.