Return to Forever (永遠への回帰 Eien e no kaiki?) is the third and last episode of New Mobile Report Gundam Wing: Endless Waltz OVA series. It first aired on July 25, 1997 in Japan and November 10, 2000 in North America.
Heero maneuvers his shuttle alongside the capsule containing Wing Zero and ejects from the shuttle. He gets inside, breaks the capsule open, and heads for Earth.
On Earth, the Brussels presidential residence is lowered into the ground. While Wufei sits in orbit of Earth, he thinks about how before Operation Meteor he clashed with Master Long over the decision to drop the Long clan colony, A0206, on Earth. Heero arrives at Earth, and Wufei attacks him. As they fight, Wufei tells Heero that Earth did not change after the Eve Wars. He says that to determine whether peace peace at the expense of lives could truly be called peace, he will become evil itself.
Duo breaks free from prison and finds Trowa sitting in a shuttle. Trowa says he is waiting for Sally, and she arrives after rescuing some hostages. In Brussels, Zechs and Noin fight off the Serpents with only the Taurus and the Tallgeese III. Their battle is more difficult because they are disabling the suits, not destroying them. Heero and Wufei continue to fight and enter the atmosphere, Wing Zero's thrusters are damaged during reentry. Heero tells Wufei that Treize is dead and his fight is over. Wufei says that he still fights Treize everyday, and that they both know they can only acknowledge their lives on the battlefield. Quatre, Trowa, and Duo reclaim their Gundams and head for Earth. Relena tries to make an announcement to the people, but Dekim stops her before she can finish.
As Zechs and Noin are outnumbered, they receive help from the Gundams. Heero and Wufei continue fighting, but Wufei gains the upper hand since Heero has been holding back and resisting the ZERO System's instructions. Heero asks how many times he must kill that girl and her dog. He then deactivates his heavily damaged thrusters and crashes into the ocean. Wufei is affected by this and has a flashback of his colony being destroyed, realizing that history would repeat itself if the Mariemaia Army succeeds.
The Gundam pilots, Noin and Zechs managed to disable many Serpents. However, they eventually ran out of energy and ammunition. Duo says that they can take out half of the remaining Serpents if they self-destruct but Trowa objects, saying they need to limit the casualties to themselves. Just then, Heero arrives at Brussels, floating over the presidential residence with the battered Wing Zero and begins firing his buster rifle at the presidential shelter. Mariemaia begins to panic as the shelter collapses. Lady Une, who has infiltrated the shelter earlier, saves Relena and Mariemaia, saying that she cannot allow Treize's daughter to die. After the third shot, Wing Zero explodes and crashes on the ground.
Citizens began protesting the Mariemaia Army and Wufei joins them in the Altron, saying that battles aren't decided by soldiers and that his battle with Treize has finally ended. Dekim does not accept defeat and tells Mariemaia to assume her position as the leader of Earth sphere immediately. Mariemaia, saying that she is victorious, was about to do as he said when Lady Une stops her and prepares to slap some sense into her. However, Relena does it instead, saying that it's time for her to open her eyes and realize her mistakes. Dekim is about to shoot Relena, and Mariemaia takes the bullet. Dekim does not care, saying that he could make another Mariemaia and prepares to shoot Relena, but he is then killed by one of his own men for betraying Treize's ideals. Heero enters the room and offers to end Mariemaia's pain. He shoots his gun, but it turns out to be empty. Heero says that he no longer has to kill anyone anymore and collapses.
As AC 197 begins, the world is peaceful once again. Duo, Quatre, and Trowa destroy their Gundams together. In China, Wufei destroys Altron. Sally asks him to become a Preventer, and he agrees. Zechs and Noin leave Earth to help terraform Mars. Lady Une adopts Mariemaia and takes her to visit Treize's grave. Duo returns to a colony with Hilde and continues their scrapyard business, and Trowa reunites with Catherine and rejoins the circus. Quatre parties with the Maganac Corps, and Heero watches Relena give a speech. Now that peace has been achieved, Mobile Suits, including the Gundams, are never seen again.