Santiago from Portugal, Marek from Poland and Aleksandra from Serbia, all participating in an eTwinning project, met in Lisbon. Enchanted by the Portuguese culture, they enjoyed pasteis de nata, a type of custard tartlet, and explored the Jeronimos Monastery and the Belem Tower.

Visiting Sao Jorge Castle, they were captivated by an intriguing painting of Saint George and the dragon. While examining this painting, they noticed something peculiar - ancient symbols and mysterious inscriptions surrounded it. As they studied them, they realised those inscriptions could be an ancient passage to a parallel world. When they touched the symbols, a mysterious light emerged from the painting, completely surrounding them. Suddenly, they found themselves transported to an unknown landscape, very different from Lisbon.

In the world beyond the painting, they encountered Saint George and the dragon interacting in unexpected ways. They discovered  that in this realm, Saint George was not only a warrior but also a guardian of ancient wisdom, while the dragon symbolized the mysteries of the universe.

During their conversation with Saint George and the dragon, the three friends learned that the painting acted as a portal to a hidden realm - a space where myths and legends came to life. However, their presence in this realm caused a disturbance, threatening the stability between the two worlds.

After this revelations, Saint George and the dragon agreed to help their friends to return to their world. Nevertheless, the three friends now carried a new burden: guarding the secret of the painting and maintaining harmony between both worlds to prevent unimaginable consequences. But, due to a mysterious enchantment, they were transported to Warsaw, in Poland, instead of Lisbon.

While exploring Poland, the friends decided to visit the famous Wieliczka Salt Mine, known for its underground galleries and the rich history of the miners who excavated it centuries ago. The friends were fascinated by the ancient inscriptions and underground tunnels that revealed the miners' history. Deep within the mine, they discovered a forgotten tunnel and a series of inscriptions  mentioning a lost city. 

The inscriptions spoke of a long-forgotten mystery, a city that no one knew existed. Determined to solve this enigma, the friends continued to explore the tunnels until thel found a hidden cave. Inside it, they discovered an ancient room with murals reperesenting a lost city in time. Each painting told a different story about this mysterious city. As they studied the murals and solved the enigmas hidden in the paintings, the friends realized that the lost city was real, and its ruins could be burried somewhere nearby. The three friends were really excited about discovering the mysterious city that seemed to exist only in the secrets hidden in the depths of the salt mine.