Buso Renkin summary: The narrative of Buso Renkin centers around Kazuki Muto, a brave teenager who sacrifices his life to rescue a girl from a savage assault. The next day, he wonders if it was just a figment of his imagination, only to discover that the girl, Tokiko Tsumura, and the monster are tangible beings. Tokiko desired to exterminate the homunculus - aberrant creatures that assume human guise and feed on people - but Kazuki meddled. In order to revive him, she implants a "kakugane" - an alchemical device that empowers him to summon a lance to confront the homunculi. Tokiko is a Renkin Kenshi (an Alchemist Warrior) who protects the world from evil beings. Hence, Kazuki joins forces with her to obliterate the nefarious entity that creates and governs the homunculus.