New Seoul had to be rebuilt after the invading dimensional monsters were defeated. The Closers were responsible for securing the city from any further attacks. Global chaos ensued when mysterious dimensional gates opened and unleashed a worldwide invasion of dimensional monsters that could not be stopped. Amid the destruction, the psychokinetic power that was awakened by the gates granted extraordinary powers to a small number of humans. Governments were able to use these psychic warriors to eventually close the gates and bring the First Dimensional War to an end, which also marked the birth of the term "Closers." In the aftermath, research into the dimensional gates and psychokinetic power allowed for the creation of the organization UNION. They worked tirelessly to prevent another invasion from happening. However, when the dimensional gates started shaking once again, Closers had to band together to defend the world from yet another attack.