How to unlock: The quest will start in the Diamond City Market (M6,1) automatically after completing the Jewel of the Commonwealth main quest.
- Find Nick Valentine
- Free Nick Valentine
- Talk to Nick Valentine
- Follow Nick Valentine
Finding Nick Valentine
You will receive this quest after meeting with Ellie Perkins in Valentine detective agency in Diamond City. The woman will send you in search for the detective. You must go to the hideout of the local gang related to the investigation led by Valentine. The hideout is in the Park Street Station northeast from Diamond City. Once you reach the destination, find the entrance to the metro tunnel and use it.
A long trip is ahead of you. During the trip you will face many groups of enemy triggermen. You should attack each group by surprise and hide behind cover once the battles start. Luckily, the enemies will be mostly using weak pistols (regular and machine ones). Keep walking, first exploring the station and then going along the tracks. They will lead you to the Vault 114 hidden in the tunnels. Press the red button in order to unlock the entrance to the vault.
Sadly, you will be regularly attacked by the gangsters while exploring the vault. The first group will be found at the entrance to the crypt, it is a good idea to attack them from a distance, as only a narrow, uncovered metal balcony is leading to them. Further in the vault you should watch out in the larger, darkened room. You should use a rifle or other similar weapon once you get there.
Freeing Nick Valentine
The detective whom you seek is held in the last part of the vault, in the Overseer's room. He is guarded by Dino, a more important killer in the ranks of the gangsters. If it is possible, surprise attack him (for example, with a shot from long distance), not allowing him to defend himself. You can get to the room with Nick Valentine in two ways - by using the Overseer Door Password found at Dino's corpse or by hacking into the terminal on the right. Enter the office and talk to Valentine.
Important - There is a bobblehead in the room with Valentine, you will find it on one of the tables. Picking it up will increase the limit of bottlecaps that the merchants can use.
Escaping with Valentine from Vault 114
Follow Nick Valentine. On your way to the surface you will meet new triggermen. Luckily, you don't have to worry that your new ally will die during the battles. However, it is wise to keep him in his full strength, thanks to that you will receive help from him.
Just after you get to Park Street Station, you will be stopped by Skinny Malone and his men. This encounter can have few outcomes. If you play as a character with high Charisma level, you can try convincing Darla who is accompanying Malone to escape or to turn against her lover.
If you have chosen a peaceful solution, there is a chance that you and Valentine will be also able to leave the location before Malone changes his mind. If the persuasion attempt failed or if you decided to fight, then the battle will start. During it, you should use shotgun or other weapon that is useful on short distance - you will have nowhere to hide. Luckily, Malone and his men aren't a great threat.
No matter how you behaved, follow Nick Valentine. He will lead you to a hatch you previously bypassed in the metro tunnels. The hatch will allow you to return to the surface. Use it and talk to the detective, who will tell you to meet him in his agency in Diamond City.
Quest rewards: Experience points, new main quest (Getting a Clue).