The story takes place in the "Thunderbolt Space" where a base colony was destroyed in the war and a large number of warship wreckages are floating. The Space is the supply route to the ZEON Principality fortress "ABaoAQu". In order to recapture the Space, the Earth Federation Army and the ZEON Principality launched a fierce battle. Lieutenant Io Fleming and others of the Earth Federation Army boarded the GM204F and sneaked into the Thunderbolt Space to challenge the sniper.