The "Extracurricular Detective Group" series of campus detective novels is a series of juvenile detective novels created by Mr. Xie Xin. The story takes Midosi, Ma Wei Ka and Ou, three children who love reasoning and exploring cases, as the protagonists. Because of their common interests, they formed a small group called "Extracurricular Detective Group". With the support of Magicmaid, the cousin of Interpol Midosi, after careful observation, careful analysis, calm reasoning, bold assumption and decisive action, they finally solved all kinds of confusing puzzles. The book is full of twists and turns, wonderful stories, relaxed and fashionable language humor, easy to understand, and pays attention to logical reasoning, popularizing scientific and legal knowledge. It is the best reading for children to increase their knowledge and improve their wisdom.