Super Robot Taisen W is part of the Super Robot Wars franchise and was published for the Nintendo DS by Banpresto. It is the first Super Robot Wars game released for the Nintendo DS. Like some DS games, special features can be unlocked by starting a new game with any of the Game Boy Advance era games inserted into SLOT 2.

Space Calendar (SC) 99. In the previous age, the governments of Earth formed the Federated Earth Nation (FEN) to bring World War III to an end. After putting down the defiant lunar colony, the Federation Space Calendar was instituted. To alleviate environmental pressures and overpopulation, the FEN began expanding into space, constructing space colonies and asteroid cities, as well as an Orbital Space Ring around the Earth, and the development and terraforming of the Moon and Mars. This was accomplished in a short time, due to quantum leaps in physics and energy research.

But repression of those living in the colonies by the FEN ignited a war between factions in space, and OZ, the true leaders of the FEN. This "Revolutionary War" ended in the year 98, with the death of FEN President Treize Khushrenada. From Treize's will, a New United Nations was formed, returning power back to the individual states.

But the new Earth Sphere's troubles seemed to multiply. The Earth Sphere was invaded by the Radam, who seized control of the Orbital Space Ring, and the invaders known as the Jovian Lizards, who destroyed the Mars Colony. In addition, internal strife, such as the arbitrary distinction between Coordinators and Naturals, and mechanized terrorism, seem to be taking the New United Nations to the breaking point.

On June 13, SC 99, Kazuma Ardygun and his family, a group of Trailers, are tasked with the job of escorting Quatre Raberba Winner and Duo Maxwell, disguised as "Heero Yuy", to Earth...