The epic conclusion to the Ideon saga, featuring what was meant to be the final 5 episodes of the TV series. The Solo Ship and its crew continue their intense battle with the Buff Clan leading to a final battle that will determine the fate of all life in the universe. 
This movie features the last episode of the TV series Space Runaway Ideon (39), and four more episodes (40-43) that were meant to air on TV, but never did since the show was cancelled. 
This movie was the second part of a double feature along with "The Ideon: A Contact".
 
(Source: Anime News Network)

From the continuing reclamation of the ruins of the planet Solo, mysterious mechas are excavated. But suddenly, an alien called Buff Clan attacks seeking the limitless energy “Ide.” The earthlings are backed into a corner, when the three mechas piloted by the earth boy Yuki Cosmo and others fuse together. Becoming the giant robot Ideon, they use their incredible power to fight back against Buff Clan. 
(Source: Sunrise)

A movie recap of the Space Runaway Ideon TV Series. Humanity's pursuit of knowledge leads them to the planet Solo, where they find mysterious remains of a long dead alien civilization, including the 3 part super robot 'Ideon', and a powerful warship. Using these, the Earthlings sent to investigate the ruins defend themselves in their constant conflicts against powerful aliens called the Buff Clan, who are in pursuit of 'Id', the mysterious energy that powers the Ideon.
 
(Source: Anime News Network)

Daram Zuba