Secret Agent Leonard is the first mystery story series in Korea to feature Brown & Friends, the globally popular character brand. Leonard, the original Brown & Friends character, transforms into a mystery detective who solves puzzling cases that spark curiosity in children around the world. From mysterious beings like zombies, Dracula, and the boogeyman to strange phenomena such as the Bermuda Triangle and poltergeists, this series brings readers face-to-face with the truth behind mysteries everyone has wondered about at least once. As suspicious characters appear around mystery-solver Detective Leonard, new stories unfold one after another. Each tale offers clues leading to the next case, with unpredictable twists and turns that keep readers on the edge of their seats until the very end. Get ready to uncover the secrets behind each mystery and cheer on Detective Leonard's brilliant adventures!