On her fourth year in Sweden, Carol finally decides to have a long summer vacation, reading novels in her hammock and looking after her allotment. However, her vacation is soon interrupted when she receives a letter from a friend visiting Paris. The person he's travelling with has just gotten a message that a vagrant has been killed in his Swedish apartment, after sneaking in there to sleep. Starting off with no clues at all, Carol is soon wrapped up in her longest and most complex case to date.