The sixth book in the series is an adventure by the most beloved author of children around the world.
The four beloved friends, Jack, Lucy-Ann, Philip and Diana, are looking forward to the summer holidays. They will cruise in the Mediterranean, starting in Portugal, to reach the Aegean islands.
Lucian, a 15-year-old boy with funny glasses and discarded teeth, will board the Naples. A strange story will be told in the company about a hidden treasure on a Greek island. The children are determined to reach the island of Rhenia, where they will experience a unique adventure in underground tunnels, labyrinths and catacombs, searching for the mythical treasure.
What will the map reveal with the Greek words unknown to the company? Who is the strange Mr. Epikopoulos and what are his plans to seize the treasure? Are you ready for adventure?