Area51 - Test Site

In the eleventh year of the Meiji era carrying swords was forbidden by the government and those known as samurai were slowly fading away; however, there were plenty who didn't like those changes taking place in Japan and inevitably the crime rates increased. The country's only solution was an inescapable lake prison. Since the prison had no other way to access it except by water, the three boys of the Kumo family were assigned to transport the criminals to their new "home." Although, is that the only thing they were doing...?

One night, Kazuki Muto jumps in to try to save what he thinks is a girl in distress from a monster and instead gets impaled through the heart. The girl, Tokiko, is actually an alchemic warrior with a Busou Renkin, name of Valkerie Skirt, with the mission to exterminate Homunculi. She implants the only other successful work of alchemy than the Homunculus, the Kakugane, to take the place of Kazuki's heart. The Kakugane resonates with his fighting spirit and forms a Busou Renkin (in his case a spear) so he can fight the Homunculus monsters who prey on humans.

A former gymnast, Aikawa Maki has turned her skills to a different way of life - street fighting. The only thing that truly makes her feel alive is violence. With amazing power and grace, she fights opponent after opponent, repeatedly demonstrating the gymnastic talent that earns her her nom de guerre, "Airmaster".