Záhada hlavolamu (Mystery of the Puzzle) is a Czechoslovak adventure television series produced by Czechoslovak Television, which broadcast it in 1969–1970. The nine-part series is an adaptation of the novels The Mystery of the Puzzle and Stínadla se bouří by the writer Jaroslav Foglar. It was filmed by director Hynek Bočan, who is also the author of the script with Václav Šašek. The series focuses on a group of boys from the Rychlé šípy Club who venture into the mysterious urban district of Stínadla, where they uncover various local secrets.Roles of older boys (Vonts) and adults were mostly played by well-known actors, while only Roman Skamene, who was fifteen at the time, continued to work in the acting profession from the representatives of the Rychlé šípy.