Strange portals called "Gates" are leading to "Dungeons" filled with monsters. People called "Hunters" are traveling through these portals to fight monsters that reside there. This is the crazy world of Ertha, but people have gotten used to it. Years after the disappearance of your family, you are awakened as a Hunter. Unfortunately, you are an E-Rank Hunter, the lowest rank. But that doesn't stop you from finding yourself battling monsters inside Dungeons and fighting alongside higher ranked Hunters. However, not everyone you meet are what they seem. And soon you are dragged in a mystery plot that will involve finding out your past. Why are the Gates appearing? What happened to your family? What is hiding inside you?