"The Super Dimension Century Orguss" is a science fiction mecha anime set in a universe where Earth has been devastated by a catastrophic war. The story begins in the year 2062, where humanity has developed advanced technology, including powerful mecha known as Orgroids. The protagonist, Kei Katsuragi, is a skilled pilot working for the Earth Federation. During a mission to test a new weapon, Kei inadvertently triggers a mysterious device called the Decimation System, which causes a dimensional rift. This event fractures the timeline, merging multiple parallel worlds into a single, unstable reality known as the "Super Dimension."

Kei is transported 30 years into the future, where he discovers a world drastically altered by the dimensional collapse. The once-unified Earth is now a patchwork of conflicting timelines, with different civilizations, species, and technologies coexisting in a chaotic and often hostile environment. Kei becomes embroiled in the struggle to restore the original timeline, aided by a diverse group of allies, including the enigmatic woman Mimsy and the warrior princess Anita. Together, they navigate the complexities of this fractured world, encountering factions such as the militaristic Mu Empire and the technologically advanced Olbanians, each with their own agendas.

Central to the narrative is the concept of the Decimation System, which holds the key to reversing the dimensional collapse. Kei and his companions must locate and control this system while contending with rival factions seeking to exploit its power for their own purposes. The story explores themes of identity, coexistence, and the consequences of tampering with time and space. As Kei uncovers more about the Decimation System and its origins, he is forced to confront difficult moral choices, including the potential sacrifice of the new world and its inhabitants to restore the original timeline.

The series balances action-packed mecha battles with character-driven drama, as Kei and his allies grapple with personal conflicts and the broader implications of their mission. The narrative builds toward a climactic resolution that addresses the fate of the Super Dimension and the possibility of reconciliation between its disparate elements. Through its intricate plot and exploration of alternate realities, "The Super Dimension Century Orguss" presents a thought-provoking and engaging story within the mecha genre.