The story was based on an online game "Age of Gunslingers". Main character lin xiao shuai whom lost his parent at a very young age and due to his sickness he has inhereded his father friend's DNA in order to live; an legendary ranked agent who specialize using guns. xiao shuai was taken to the secret organization for training in order to become an agent and fighting to prevent evil organizations from taken DNA from the DNA lockbox. This anime is very good because each character is unique and the characterization setup for each stage is well written. The best part is that inthis anime all the fight scene is pretty good and if i were giving an fight animation only rating it would be an outstanding 10 despite it is a 3dcg.