Frederica Hanashiro from the Ministry of Foreign Affairs visits the Public Safety Bureau with the intent to make an offer to Teppei Sugou, one of the current Division 01 Enforcers. Since Sugou was once an ace pilot in the National Defense Army, Frederica gives him the opportunity to clear his status as a latent criminal and rejoin the military.

As he considers the offer, Sugou recalls his days in the army. While carrying out a mission, Sugou's First Guardian drone was ordered to drop supplies and abandon a ground unit—including his commanding officer, Itsuki Ootomo. All of the members in the group were proclaimed missing, but it was evident that they marched to their deaths.

However, three months later, during a massacre at the Ministry of Defense, the security cameras caught none other than Ootomo at the scene. Now considered a suspect in aiding a terrorist attack, Sugou works together with Inspector Risa Aoyanagi and Enforcer Tomomi Masaoka to get to the bottom of the case.

[Written by MAL Rewrite]