An Assassin

Hanaki Ryo was raised to be a professional assassin. During one mission, though, things go horribly wrong after an attractive high school girl named Rio accidentally gets in the way. Hanaki has always spent days as a heartless assassin, but his life starts to change after he helps Rio. By a twist of fate, Rio, who was a complete unknown, suddenly becomes a target overnight. A single mistake from his decision to save Rio has seemingly decided the destiny of the masses.
(Source: fareastfilms)