Quatre, now mentally unstable, appears in the newly-constructed Wing Gundam Zero and begins to destroy various colonies one by one. Lady Une sends Heero and Trowa to fight back in the Mercurius and Vayeate, while Tsuborov, finding Une's behavior to be too lenient, stages a coup against her and cuts off the air supply to Wufei, Duo, and the Gundam engineers' cells.