The Carnival Master, the fourth book in the Jan Fabel series, sees the Hamburg police chief drawn into a terrifying case just as he prepares to leave law enforcement. A serial killer strikes at the start of Cologne’s famous Carnival each year, and a local detective seeks Fabel’s expertise. Meanwhile, his assistant, Maria Klee, is secretly hunting an even deadlier criminal, and a Ukrainian Special Forces team arrives with a ruthless mission of their own. As the chaos of Carnival unfolds, Fabel is pulled into a world of betrayal, revenge, and masked identities—where he must face his greatest enemy yet.