The Dan Detective School is a Japanese detective school permitted by the government. Kyu, an ordinary boy with big dreams to become detective, attends the school as a member of Q Class along with Megu, the girl with photographic memory; Kazuma, the computer genius kid; Kinta, the strong; and the mysterious Ryu. Together they solve many cases which bring them to face Pluto, the crime organization which should have been destroyed by Dan Morihiko.