20XX is a year of crisis. Disasters, diseases occur all around the world. Rumors about war, apocalypse start spreading on on the Internet. Feeling insecure about the future, people lost control of themselves. The situation in the small country X is nothing different. Corruptions, crimes make people's trust in authority drop, terrorism's on the rise. On the outside, a big neighbor country (Y) shows intention to invade. In that context, everyone start to learn the way to protect themselves before the dangers lurking all around. Thus begins a new era, which's also leter refered as 'The era of Heroes'.

(Source: MangaDex)