An space exploration expedition is protected by an unique armored combat group that can combine into one giant robot when necessary.

The Earth is facing a huge problem, over population. A second planet has to be sought out for the citizens of Earth. Therefore, an expedition fleet is sent out to find a suitable planet. There are battles in this series. If all fails, Dairugger XV is used to defeat the baddies.—Sentaigo^_^

Planet Earth is experiencing a time of prosperity, and humanity launches a mission to explore and colonize the galaxy. The Rugger Team of explorers is attacked by the xenophobic Galveston Empire, which is also trying to establish new colonies. The Empire's home-world is facing destruction, but the despotic Emperor Corsair refuses any diplomatic attempts at peaceful co-existence. Eventually the Empire faces rebellion from within. The Rugger Team tries to find a new home-world for the desperate people of the empire, who have to flee from a dying world.—Dimos I