Dawson Eida, a young man who just graduated second in his class from the Amatsu Kowa National Officer School, is given the rank of 'Special Lieutenant' along with a peculiar assignment. Due to the school principal's scheme, his role is to work as a space pirate under the control of the enemy, the Human Unified Nation Space Union, commanding a privateering spaceship. His only support from Amatsu Kowa is the privateer ship, the <<Big Jaw>>, and initial supplies. His only companion is Oine, a communication AI. Though the mission is unreasonable, Dawson uses his false identity as a pirate to interact with other pirates, seeking ways to harm the SU and benefit Amatsu Kowa. No one knows what kind of military career Dawson will have as a result of this pirate mission.