Detective School Q

Detective School Q (探偵学園Q, Tantei Gakuen Kyū) is a manga series, written by Seimaru Amagi and illustrated by Fumiya Satō, originally serialized in Kodansha's Weekly Shōnen Magazine between 2001 and 2005, spanning 22-tankōbon volumes. It was adapted into an anime series, produced by Pierrot, spanned 45 episodes, and aired in Japan on TBS and the anime television network, Animax, who have also later broadcast it within respective networks across Southeast Asia, South Asia, East Asia, translating and dubbing the series into English and other languages.

Plot
Tantei Gakuen Q is a series about 5 students trying to become Detectives. These 5 students were the best among everybody else in the exam. They were chosen to be part of Class Q, Where the famous Dan Mohoriko will chose his successor. They solve crimes, mysterious disappearance and along the way found out about an organization called Pluto.