Unlikely Valentine

Unlikely Valentine is a main story quest and achievement/trophy in Fallout 4.

Detailed walkthrough
After speaking to Ellie Perkins, it is revealed that Nick Valentine is being held captive in Park Street station. The station is filled with feral ghouls, but inside the station is the entrance to Vault 114. The vault is guarded by Triggermen armed with submachine guns and 10mm pistols. The player character needs to fight their way through the vault until they come to a large open atrium. Upstairs is Dino guarding the overseer's office where Nick is being held. Sneaking close allows the player character to listen to a conversation between Valentine and Dino where Valentine convinces Dino that a crime boss is upset at him about his cheating habit during gambling. Dino then runs out of the room to square things off with said crime boss leaving the coast clear to free Valentine. Alternatively, Dino may be killed without waiting for him to leave. The control panel next to the office door can then be used to free Valentine.

Speaking with Nick reveals why he is there and that they should leave as soon as possible. On the desk behind him is the Speech bobblehead. After talking with Nick, he will take the lead out of the vault where Skinny Malone and Darla will be waiting to stop the escape. With a few speech checks it is possible to turn them against each other or leave the vault without fighting at all. If a certain stage of the quest The Sight with Mama Murphy has been completed before coming to the vault, there will be an additional speech option that allows escape without any violence. Otherwise, the Sole Survivor and Valentine will need to kill Skinny Malone and his companions in order to leave.

After exiting the vault there is a short conversation with Valentine where he directs the Sole Survivor to meet him back at his office in Diamond City. Upon arrival, speaking with Ellie will end the quest.

Behind the scenes
The premise for Nick being in the vault is similar to the story from the film The Big Lebowski, in which a private detective is hired to track down a family daughter-turned-crime boss' trophy wife.

Bugs
When confronted by Skinny Malone and Darla, the accompanying triggermen will become hostile if a targeting helmet is worn. Removing it will suffice. The highlight ability from berry mentats seems to make them hostile as well. nick will turn hostile and shoot Skinny Malone and Darla but will not shoot the trigger men.

Un Valentín muy poco santo Валентайнов день Sei mein Valentine