Secret of the Medallions Taiyô no ko Esuteban : Season 1 Episode 12

The Spanish army follow Esteban and his friends to the Fort of the Black Eagle. Under cover of darkness, the Spaniards attack the fort, but Tao devises a rocket flare that repels the attackers, saving the fort. The three children leave the fort and at last reach the City of the High Peak, whose chief, Kraka, tells them that the medallions Esteban and Zia wear can open the doors of Sela, one of the Cities of Gold.