In Sheep's Clothing

In Sheep's Clothing is a side quest in Fallout 4.

Detailed walkthrough
This quest begins when the Sole Survivor travels to Diamond City after they have completed Political Leanings and have been banished from the Institute, or if this condition is not met, after completing The Nuclear Option and finishing the main storyline.

Gatekeeper Danny Sullivan will be seen dying in front of the walkway leading to Mayor McDonough's office. He will explain that he was shot twice in the stomach by McDonough before falling off the elevator when he saw the mayor conversing with a synth from the Institute. Upon reaching the office's front doors, Piper or a security guard will be seen attempting to gain entry to apprehend him.


 * 1) Chase McDonough to his office. (Optional) Talk to a doctor and bring them to tend to Danny's wounds. One can also choose to use a stimpak to heal him. If Curie is the current companion, she can be asked to take care of him, which she will be happy to do.
 * 2) Break into McDonough's office and confront him with Piper. One can either choose to lockpick the door, which is a Novice lock, or use a button located underneath the secretary's desk. If using power armor with the jetpack mod, one can also enter through the window. Piper, Nick and Danse will dislike picking the lock because the door is marked as owned, making lockpicking count as trespassing.
 * 3) Decide how to deal with McDonough. Passing a medium difficulty speech check will convince him to release his hostage. He will then request that the Sole Survivor allow him to safely leave the city, giving them three options: comply with McDonough's request to leave, kill McDonough or sentence him to stand trial, which results in McDonough making a last stand.

Behind the Scenes
The phrase "a wolf in sheep's clothing" is an idiom used to describe those playing a role contrary to their real character with whom contact is dangerous.