The story takes place in Tokyo Butei High School, a special school where armed detectives—"Butei"—are trained to use weapons. Kinji Tooyama is a second year student who has a special ability, but he keeps it a secret to maintain an ordinary, peaceful life. However, when he gets caught in a bombing on the way to school, he encounters H. Aria Kanzaki, the most powerful S-Rank Butei student in Assault Studies.

Alternative title:

Aria the Scarlet Ammo DVD (TV) Limited Edition: Complete Box Set Episode:

• 1. La Bambina
  
• 2. Aria The Quadra
  
• 3. First Mission
  
• 4. Butei Killer
  
• 5. Butei Charter, Section 1
  
• 6. The Shrine Maiden of Hotogi
  
• 7. Caged Bird
  
• 8. Durandal
  
• 9. Honey Trap
  
• 10. Special Training
  
• 11. Infiltration
  
• 12. Vlad