AN:This is a story that starts a year after Fallout 4, takes place in the Commonwealth, and uses and alternate ending where the Brotherhood of Steel and the Minutemen worked together to destroy the Institute. However, in this universe, the BoS never pulled the Institute mainframe, and as such, never accessed the Institute records, and never found out Danse is a synth. In this universe, the Sole Survivor(Nate) never joined the BoS, but did make an alliance between the BoS and the Minutemen. The pairings are Preston/OC, SS/Piper, Danse/OC, and others that I haven't decided on. Enjoy.
Preston Garvey smiled as he looked around Sanctuary, and thought about just how good their group had it. He had thought they were going to die, alone in the Museum of Freedom, slaughtered by raiders, and left to rot. Instead, Nate had found them. Dressed in only his vault suit and a bit of leather armor, and backed up only by the wandering dog, Dogmeat, Nate had appeared from the other end of the road and charged the raiders. He had lunged, firing his 10mm pistol with deadly accuracy, picking off three of the six raiders in seconds. Another raider had charged the man, only for Dogmeat to strike, throwing the attacker to the ground and tearing the man's throat out. The last two raiders fell just as quick, to headshots from Nate's 10mm.
Then Nate had charged inside scooping up Aidan's laser musket, and launching himself headlong at the raiders inside. He had brought the first two down with charged blasts from the laser musket, before charging out of sight. A moment later he re-emerged, holding a raider by the neck, and shot the man. Nate had then rushed up the stairs, disappeared into the second floor rooms before jumping out of nowhere and killing the raiders outside the door. He had caught onto Sturges' plan to repair the power armor on the roof quickly, and had even already got the fusion core from the basement.
Once he had the power armor, their rescuer had sliced through the raiders outside like a hot knife through butter, his minigun wiring. Then a Deathclaw had rushed from the sewers, and attacked the power armored hero. Facing it down with brave determination, Nate had killed the Deathclaw too, cementing his role as a hero in Preston's mind. The few raiders still alive had broke, running in terror from the armored man. Nate had headed back to the group, and they had all left for Sanctuary. Preston had never looked back.
When the group had first reached sanctuary, it had been nothing, just a bunch of ruins with a lot of scrap. Now they had near 40 settlers living in their community. They had established farms and a water purification system. They had build walls, homes, and a system of walkways behind the walls, with turrets positioned on guard towers. They had stables for Brahmin, and training area for new recruits to the Minutemen. Nate had readily accepted the position of General, eager to do some good, and under his guidance, the Commonwealth was prospering. When the Brotherhood of Steel had arrived, the Nate, Preston, and the Minutemen had helped them destroy a small underground group that had been harassing the Brotherhood. With the Railroad gone, the Brotherhood and the Minutemen had assaulted the shadowy Institute, working together to destroy their common foe. Now the two factions worked together, protecting the Commonwealth.
Preston turned as the Vertibird touched down on the recently-constructed landing pad. The General, stepped lightly down from the aircraft, followed by Elder Maxson, newly re-instated Paladin Danse, and Paladin Brandis. Today was the day, the day that the Gunners would get what they were due. With the Institute nothing but an irradiated hole, and the raiders all but eradicated, the Brotherhood and Minutemen had recently turned their eyes to the Gunners, a ruthless organization with masses of weaponry. Their assault force was assembled outside the Gunner stronghold of Quincy, all that was left was for Preston and the others to meet them for the beginning of the battle. Preston easily climbed into the Vertibird, and grabbed a hanging strap as the aircraft took off.
Nate stood in the Vertibird as the aircraft flew off in the direction of Quincy. Preston was facing away from him, and as the flew, he pulled something from the pocket of his duster, and sighed softly. Preston looped the chain of the small locket through the strap he was holding, and moved over to Danse and Maxson, pulling out a map of Quincy as he went. Nate quickly checked to be sure preston wasn't looking before slipping over to the locket and opening it. The locket held a picture of a woman, with dark hair and pale skin. It was clearly a close friend of Preston's, but before he could think about it anymore, he heard Preston's voice from behind him, "Her name was Anica. She lived in Quincy before-well you know what happened in Quincy. At this point I can only hope she died in the attack, because if she was captured…" He let his sentence trail off before Nate put his hand on his friend's shoulder. "Yeah. Today we avenge them. All of them Preston. The last battle at Quincy went bad, but this time we have the Brotherhood. It'll be different this time." Then Nate went back to his seat.
The rest of the ride had been mostly silent, and the first words spoken since Nate and Preston's conversation came from the young Lancer piloting the Vertibird, "We're at the drop zone, good luck Elder, General!" The three Brotherhood members jumped first, hurling themselves from the platform, their power armor ready to protect them from the massive fall. Nate and Preston had their own plan. The Minutemen had recently cleared a pre-war military outpost, and had found several parachutes. As Nate and Preston jumped from the Vertibird platform, they grabbed the cords of their harnesses, and once they were clear of the aircraft, pulled them, activating the parachutes and slowing their descent. As they touched down, they found the three Brotherhood officers waiting for them. Elder Maxson was the first to speak, "Nate, Colonial Garvey, nice to see you survived the jump. The camp is about a half mile out. This way." The small group headed off in the direction of the camp.