Mafia is rife in America where assassinations are a regular occurrence on the streets. Inferno, a mysterious company, is behind most of these dealings through the use of their near-invincible human weapon, "Phantom." One day, a Japanese tourist accidentally witnesses Phantom's latest murder. Desperate to escape, the tourist hides in a secluded building. However, Phantom, revealed to be a young woman named Ein, and the leader of Inferno "Scythe Master" captures the tourist and brainwashes him. Given the name "Zwei," this once peaceful tourist is now a puppet of Inferno with no memories. Drawn into a world of lies, deceit, and violence, Zwei must fight to survive, hopefully to one day regain his memories and escape from this world where he is constantly on the brink of death. A spate of mafia assasinations occurs in America, the work of the mysterious organization named Inferno. “Phantom” is their most strongest and capable assassin, however a lone tourist witnesses Phantom’s latest act of murder. He unwittingly exposes the top assassin’s true identity, a young girl named Ein. Witnesses are usually killed, but the man is captured and taken to be brainwashed into “Zwei”, Inferno’s newest assassin, with no memory of who he is. From this point on, Zwei is drawn into a world of conspiracy, deceit and violence.