Reunions

Reunions is a main story quest and achievement in Fallout 4.

Detailed walkthrough
Dogmeat finds the scent of Kellogg and leads the party out of Diamond City, stopping at a small pond to the south. There is another San Francisco Sunlights cigar that needs to be picked up and shown to Dogmeat to continue the search. He follows the trail along the railroad tracks, where mole rats and other creatures may be encountered. At the underpass, Dogmeat will stop in a doorway. On the railing next to the doorway there are signs of Kellogg's blood, showing the bloody rag to Dogmeat will continue the search.

The trail continues across a bridge to the remains of an assaultron that can be spoken to for more clues. Depending on which way Dogmeat leads the party through the forest, there is a possibility they will run into a deathclaw sleeping in a small cave. On the outskirts of Fort Hagen, there are bloodied bandages on a fence that are the next clue for Dogmeat to follow. Eventually, the trail leads to the entrance of the fort where the doorway has been blocked.

Enter Fort Hagen, either by a roof hatch or through an exit door in the underground parking lot. Inside the facility are numerous synths and automated turrets guarding the building. The energy weapons bobblehead can be found in the kitchens of the command center. Deep in the facility, Kellogg begins talking to the Sole Survivor via the building's intercom, advising them to turn back. Eventually, the Sole Survivor comes to an office with a sealed door where Kellogg concedes that the Sole Survivor won't leave and opens the door so they can talk. During the conversation, Kellogg will reveal that Shaun is being held by the Institute, and thus out of reach.

The conversation will end with both parties stating that the other must die and a fight breaks out. After Kellogg and his bodyguards have been killed, a nearby terminal will reveal clues on where to continue the search for Shaun. The password for the terminal can be found on Kellogg's body, along with his cybernetic brain augmenter which is needed for the next quest, Dangerous Minds and his unique gun, Kellogg's pistol. The terminal will unlock the security doors which leads to the exit. Note that a doorway that led into this final area will be closed and remain locked once the battle with Kellogg is started, preventing backtracking into the fort. However, the exit elevator becomes available at the opposite end of the same hall.

Upon exiting the fort, a short scene plays where the Sole Survivor witnesses the Brotherhood of Steel arrive in the Commonwealth in full force, having traveled from the Capital Wasteland on board the Prydwen, which acts as their mobile base. Several Vertibirds will escort the Prydwen as it travels across the Commonwealth. The Brotherhood will announce their arrival via a loudspeaker and state that they are coming with peaceful intentions. This starts the quest Reveille if you've not dealt with the Brotherhood before, or Shadow of Steel if you have completed the Act 1 quest arc for the Brotherhood.

Back at the Valentine Detective Agency, a conversation with Nick Valentine and Piper will complete the quest. If Nick was your partner against Kellogg, after speaking with you, he will direct you to talk to Piper at Publick Occurrences, where the next major part of the main storyline will begin.

Bugs

 * After completing the quest, Shadow of Steel may not trigger.
 * After killing Kellogg, the Prydwen may not be seen in the sky and Military frequency AF95 may not play. This can be fixed using the console command This will teleport you to the roof of the Cambridge Police Station and tell you to board the Vertibird.
 * Once Dogmeat has found Fort Hagen, he may become stuck at the front entrance until entering Fort Hagen.
 * If Dogmeat finds Ness along the way to the fort, they will attack each other endlessly, rendering the quest impossible to complete without traveling to the fort yourself.
 * After using Kellogg's terminal a bug happens where any robot companion that you have made to join you has their name reverted to Automatron. And cannot be changed. No known fixes other than reverting to a previous save.
 * Players engaging in non-standard playthroughs where Codsworth, Preston, and Dogmeat are all ignored may trigger a bug where Kellogg's dialogue does not trigger in Fort Hagen, leading to a situation where the final door will not open, despite all the synths at Fort Hagen indicating that they are defending Kellogg. This can be fixed relatively easily with and/or disabling the final door with the console. Kellogg is unable to be talked to, but can still be killed as normal to complete the quest.
 * Hacking The terminal within the fort results in a bug that prevents the mag lock doors from opening (even if you have the password).
 * If players reload to just before the final conversation with Nick and Piper, the conversation may replay from the beginning after finishing and selecting to stay with your current companion rather than go with either of them. This can happen multiple times in a row.

Wiedersehen macht Freude Reuniones Retrouvailles Dawni znajomi Reuniões Воссоединение (Fallout 4) Возз'єднання (Fallout 4) 重逢