Overman King Gainer

In a future where Earth has become largely uninhabitable due to environmental damage, people reside in enclosed cities known as Domepolises, located in various regions including Siberia. As some areas begin to recover, many Domepolises attempt to break away from their governing authorities. Gainer Sanga, a video game champion with 200 victories, is unjustly detained by the Siberian Railway during his hometown's attempt to leave. Forced into a mecha he names "King Gainer," he becomes involved in battles against other Overmen while aiding Yapan's effort to flee across Siberia.