The story is about Astor, who attends "Bagner's Adventurer Prep School", an institution that is established with the purpose of training the best adventurers. He is a hard worker with superior academic accomplishments, and also possesses innate ability. He is thought to definitely be selected as a prospective member of "Bagner's Official Investigators", but at the Arcana Judgment Ceremony, it is revealed that he has the lowest rank, 1☆, and so he is expelled from the school. Join a genius adventurer on his rising journey from rock bottom!