UB (Unlimted Blue), a legendary organization amongst the world of intelligence agencies. They do no belong to any country nor individual groups. Whether its the number of members or their whereabouts, all information about them is unknown. A secret organization known as the "other United Nation", sworn to protect this blue planet from chaos that threatens to destroy its peace.
The story unfolds around one of the top nine agents in UB, operative number 9, Code name: Musashi, and a young man named Shingo.