Siblings Finn and Joanna are excited. Although they have traveled many times before, they have never done so without their parents. They are visiting Uncle Thomas, Aunt Agneta, and Cousin Oscar for a week in Stockholm. Together with Oscar, the vacationers explore downtown Stockholm and visit the famous old town, Gamla Stan, the Royal Palace, and the Nobel Museum. On their way, they see a homeless man huddled in a corner. The three are worried about the man, who could freeze to death since it is still very cold in Stockholm in March. They approach him, but the homeless man does not respond. The man is dead! The children have discovered a corpse in the middle of Stockholm. They quickly run to the police for help. However, when they return with backup, the body has vanished. The curiosity of the three is piqued. What is going on here? Where did the body go?.