This is a sci-fi visual novel and the events are taking place both in the future (+100 years from now) and the present times.
You'll be playing as an agent, that works for a company who controls time. Their main goal is to save the humanity from horrible events.
Your job as an agent will be to go back in time and eliminate a target, however things get complicated when you realize that, this is not the usual type of target.
Good luck, saving the humanity.
