Before you begin this mission, we advise that you (fast) travel to Diamond City when it is night time. Make your way up to the Mayor’s office (there are signs for this), and you should find him sitting in an office, while his secretary is sleeping in the next room. Ignore them, but look in the front few rooms for a safe. You’ll have to have necessary perks to pick it, but once you do you should get your hands on Kellogg’s House Key. If it’s not in the safe, it is somewhere in the Mayor’s office.
Of course, if your charisma is high enough you can talk the secretary into giving you the key through conversation, or you can pay the required caps to bribe her into giving it to you. We like our way.
Once you have Kellogg’s House Key, make your way to Valentine’s office and enter. This should trigger a conversation between him and Ellie, with you interjecting when the time is right. We chose not to ask for a reward, and were given 100 caps just the same.
This is pretty simple. Look at the chair across from Nick Valentine and sit down in it. If you mess this up, we feel bad for you going forward.
There really isn’t a magic formula for this conversation. You should be able to choose every option in the conversation table, so what order you go with shouldn’t matter that much.
After getting through the first round of questions, we decided to tell Valentine that the man who took Shaun had a bald head and a scar. This led him to believe that Kellogg was responsible. Continue with the conversation until Valentine wants to go look at Kellogg’s house.
Walk with Nick until you reach Kellogg’s house. He will try the door, and then he’ll ask you to give it a shot. If you don’t have the Kellogg’s House Key, this will be the time you have to go and get it. However, we had it (and you should), allowing us to enter immediately.
If you’ve been following our walkthrough, this should already be done. If it’s not, you can view our notes on how to get the key at the top of this page. You can steal the key, buy the key, or talk your way into having it given to you. We went with the first option.
It goes without saying that Kellogg is kind of a jerk for taking your son, so it’s only fair that you steal everything in his home. Seriously, you can loot without fear of Valentine caring, and Kellogg won’t return to catch you. Take it all, and then meet Mr. Valentine by Kellogg’s desk. If you walk around to the back of it, there will be a button under the desk that reveals a secret room. Press it, of course.
Continue to loot things in the secret room, paying special attention to the shelves on the left side. When you have it all, look at the San Francisco Sunlights on the table. Picking them up is the clue that you’re looking for.
Your dog is no longer nameless, as Nick Valentine has labeled him Dogmeat. We weren’t sure what to do next, so we looked at Nick and asked for suggestions. He gave us this objective, and we showed Dogmeat the cigar as instructed. We also told Nick Valentine to come with us to find Kellogg, as he can be extremely useful in the next mission. Not only does he attract the attention of your enemies, he can also hack into just about any terminal or door, even if it’s beyond your skill level.
After you exit Kellogg’s and show Dogmeat the cigar, the mission will end. From here you can immediately continue on to the main story quest, Fallout 4: Reunions, or you can return to USgamer’s Fallout 4 Walkthrough and Guide.