Once a prince of the fallen Arcadia empire, Lux stumbles into a forbidden encounter with Princess Lisesharte in a dormitory mishap. This mishap sparks a fateful clash as Lisesharte challenges Lux, a renowned Drag-Knight turned 'undefeated weakest,' to a battle in their world of ancient mechanized weapons known as Drag-Rides. Despite his past glory, Lux now stands firm in his vow never to strike. Following this showdown, Lux finds himself enrolled in an exclusive academy where royal women are groomed to master the art of being Drag-Knights.