Spring in Rome. Everything seems enchanting for the group of young and old, who enjoy their holidays indulging in... a diet of ice cream and pizza. The Eternal City has captivated everyone, thanks to its sights. Especially the lovers! Their stay in Italy becomes even more exciting as they travel from Rome to Catania and throughout Sicily. Marina, the mother of Katerina and Zoe, combines this vacation with a journalistic success: An interview with the German tycoon Klaus Torre, who claims to support environmental protection. However, the clever group of children discovers that things are not at all as they seem. When the Calabrian mafia, the 'Ndrangheta, and the mysterious organization of the Spider come into play, the conspiracy theories that accompany them prove to be completely true. An assassination attempt will begin to shed light on the dark side of the mysterious organization's actions. The traces lead to Greece and the enchanting Ionian island of Kefalonia. There, all the friends will meet again in the summer and will experience the toughest adventure of their lives. Who is filling the Ionian Sea with toxic waste? Who is behind the trade of dangerous substances? Who wanted to eliminate an Italian activist? In their sixth adventure, the heroes will tread dangerous paths, experience moments of happiness and pain, and be enchanted by the "mysteries of Kefalonia." Some of these, however, will prove fatal...