Four tourists travel to to the Swedish island of Gotland in the month of September hoping for the time of their lives. They soon discover however that in the time of year of their choosing for the vacation, is a time of year where Swedes are anywhere but on the island. The four tourists soon discover that the few inhabitants of the island are carrying a secret; a secret that is about to make the four wish they had never come to Sweden.

The Secret

In 1361 the Danish King Valdemar's troops approached the city walls of Visby, Gotland. Meanwhile, a young woman named Sigrid was leaving tracks all over the place leading to the whereabouts of a great treasure.She was able to fulfill her mission before being captured and immured alive in a tower, as punishment for not revealing the whereabouts of the treasure. Currently Kathrine, 14, and his three friends have to follow the tracks of 700 years ago during the Medieval Week celebration in Visby to rescue his father, who has been kidnapped, and find the lost treasure. But the fearful and dangerous Black Brotherhood lies in wait.