The Devil's Due

The Devil's Due is a side quest in Fallout 4.

Detailed walkthrough
A guard in Diamond City will say that something weird is going on at the Museum of Witchcraft, and the quest Investigate the Museum of Witchcraft appears as a miscellaneous quest. The map marker leads to the body of Private Hart. However, it's not necessary to pick up this quest to do the rest of this quest line.

On the exterior west side of the Museum of Witchcraft is a body; on it is Private Hart's holotape. Upon listening to the holotape it will be clear that Hart and her crew were running from something and took cover in the museum. Enter the museum via the cellar door a few feet away from the body. While in the museum there is growling and some body parts dropping from holes in the ceiling periodically as one makes their way through. Head up to the first floor. In the room behind the closed door there is a wandering deathclaw (level dependent). Kill or sneak past the deathclaw and look around the floor in the rear bathroom to find Sergeant Lee's holotape (required to advance the quest) by his corpse. Around the body are some cracked deathclaw eggs and the pristine deathclaw egg required to advance the quest.

One then has the option to continue the delivery of the egg to Wellingham outside the Colonial Taphouse in Diamond City, where they will be awarded 200 caps (plus an additional 100 with every persuade approval) and, after an additional dialogue choice, they will receive the Wellingham's recipe note which teaches the recipe Deathclaw Wellingham. Although not noted at the time, it also adds an additional recipe for tasty deathclaw omelette.

Alternatively, one can return the egg to the nest west of Parsons Creamery where a friendly deathclaw will appear and one can find a deathclaw gauntlet next to the nest. Finally, it is possible to take the gauntlet without returning the egg, allowing one to sell the egg to Wellingham normally. The friendly deathclaw will turn hostile if one tries to leave the area without returning the egg. One can still fast travel while the deathclaw is still friendly. Simply grab the gauntlet and fast travel to Diamond City without leaving the immediate area which would make the deathclaw hostile and prevent fast traveling.

Companion reactions
Companions will react based on the decision in the quest. If one returns the egg to the nest:
 * Piper and Nick Valentine like this act.
 * Cait, Curie, Preston Garvey, Deacon, Old Longfellow and Strong dislike this act.
 * Paladin Danse hates this act.

Companions will react based on the decision to steal the egg after returning:
 * Hancock, Deacon, Cait, Preston Garvey and MacCready like this act.
 * Piper, Curie and Nick Valentine dislike this act.
 * Paladin Danse hates this act.

If one decides to deliver the egg to Wellingham:
 * Curie and Piper will like this act.
 * Paladin Danse dislikes this act.
 * If an increased reward is asked McCready, Curie, Piper and Old Longfellow will like this act.

Bugs

 * The friendly deathclaw protecting the nest will be hostile if you are wearing a targeting power armor helmet. Putting the helmet on after completing the quest by returning the egg will immediately turn the deathclaw hostile.
 * Berry mentats will also trigger a hostile status.
 * Occasionally, the quest will get stuck on "Listen to Sergeant Lee's holotape," and will not progress even after listening to the holotape.
 * When the egg is sold to Wellingham, the Private Hart and Sergeant Lee holotapes can become stuck in the inventory (try transferring tapes to Dog Meat, then putting it back into the workshop)

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