Space Fortress Ambat

The crew of the Diva, pinning their hopes on a decisive final battle, set sail for the space fortress Ambat. The drums of war rise to a fever pitch. The U.E. attack with a force of mobile suits and massive warships. In a battle unlike any they've fought before, the Diva and the combined Zalam-Euba forces clamp down on their fear and fight for survival.

Synopsis excerpt via Kitsu.