Natalia and her brother Nico have become trapped in a series of different historical time periods after going through a crevice in a cave. In their latest letter, they describe crossing the crevice again but ending up in a village that appears to be from the Iron Age, as money and metal tools have been invented. People are busy trading and the village has stone houses and walls for protection. Natalia and Nico are hoping the next time they cross the crevice it will finally return them home, as their time travel adventure has gone on long enough.