Shin Kidou Senki Gundam Wing: ENDLESS WALTZ

In the year After Colony 195, former Gundam pilots have retired their mobile suits in pursuit of lasting peace. This fragile peace is disrupted when Mariemaia Khushrenada, claiming to be the daughter of the late Treize Khushrenada, takes Relena hostage and initiates a war for independence against the United Earth Sphere Nation. The situation forces the pilots to reconsider their decision to leave their machines behind.