Thirty‐five years after the Battle of Yavin, a team consisting of the Jedi Rey, a former First Order Stormtrooper Finn, the pilot Poe Dameron, the droids BB-8 and C-3PO and the Wookiee Chewbacca journeyed to Pasaana, following the trail left by Luke Skywalker from his search for a Sith wayfinder, an object the Resistance now needed to prevent the grand plan of Darth Sidious and the Sith Eternal from reaching fruition, who had been secretly amassing a gigantic fleet, the Final Order, on Exegol, which required a wayfinder to locate, as the way to the Sith world was treacherous and uncharted. While exploring Ochi's derelict ship, BB-8 stumbled across the deactivated D-O, left alone and covered in dust. BB-8 promptly reactivated the little droid, who expressed his gratitude at being returned to life. However, when Rey reached out to touch him, the little droid backed away, not wanting to be touched, leading the Jedi to reach the conclusion that the previous owner, Ochi, had treated him badly. Rey convinced the droid it was alright, and he was now with them.
D-O joined his new friends on a trip to Kijimi, seeking the droidsmith Babu Frik to allow C-3PO to read an inscription written on Ochi's dagger, which was kept in the droids memory. While on Kijimi, Rey learned Chewbacca was alive, and alongside Poe, Finn and BB-8, D-O traveled to the Resurgent-class Star Destroyer Steadfast. While they got separated, leading to the capture of Finn and Poe, who had just freed Chewbacca, they were saved by General Hux, who had betrayed the First Order. D-O alerted 3PO that their friends were ahead, and boarded the Millennium Falcon alongside them, with Hux staying behind.
Following their escape from the Steadfast, the Falcon endured a rough landing on Kef Bir, an ocean moon of Endor, the location of the wayfinder as written on the dagger. It led to the ruins of second Death Star. D-O, curious asked what the wreck was, with Rey telling him it was the Death Star, ruins from an old war. After locating where the wayfinder was in the ruins by using the dagger, they were interrupted by the arrival of Company 77 led by Jannah, who wanted by to know what business the Resistance had on their moon. D-O curiously investigated the orbaks, but was frightened by them. After Rey left the others behind, D-O stated that he missed her. Finn asked the droid his name, but then learned that D-O had a lot of information on Exegol, which was Ochi's intended destination before his death.
The information kept by D-O, crossed with a live transmission sent by Rey piloting Luke's T-65B X-wing, Red Five, allowed the Resistance to locate Exegol and the Final Order, giving them a fighting chance at stopping the destruction that could be wrought. After a hard fought battle, and the arrival of the citizens' fleet, the remaining forces of the Sith Eternal was destroyed, and Sidious was finally killed by Rey once and for all. D-O joined the celebrations with his new friends, never again to be a slave to evil.