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.

Anders and Lotta are newly in love. Everything would be great if it weren't for Anders' partner Sofia and Lotta's husband Kurt who still doesn't know anything. Anders is an ornithologist and when he hears that a real rarity, the Mongolian Pipit, has been seen on Gotland, he sees his chance to see his three hundredth bird and become a member of the prestigious Three Hundred Club. But it also means that he can be alone with Lotta. Before they can tell their respective that they love each other, they are exposed.

Around the time that the chief of police is elected the Most Popular Citizen of Valleby, a thief and impostor is released after two decades in jail and returns to the town with a revenge plan in mind.