Something Sentimental

Something Sentimental is a side quest in the Fallout 76 update The Legendary Run.

Walkthrough
The quest starts by traveling to Foundation and speaking with Maggie. Alternatively, one can enter Monongah mine during the A Colossal Problem event and pick up a note entitled A father's goodbye, which will also lead to her.

She tasks the player character with finding a way to enter the mine for the purpose of finding any trace of her father, Earle. She mentions that a large explosion may pry the mine's entrance open. Another clue as to how to gain entrance can be found in the form of a raider's note.

In any case, the next step is to personally drop a nuke on Monongah mine, triggering the event quest A Colossal Problem, thus gaining access to the mine's interior. Progressing the event quest results in the player character finding and having to kill her father. Afterward, one can find his pocket watch on his remains.

Traveling back to Maggie will conclude the quest with different outcomes:
 * Telling her that nothing was found allows for keeping the pocket watch.
 * Telling her that only the watch was found results in losing the watch and gaining 60 caps as well as ~300 XP.
 * Telling her the truth about her father's mutation and death results in losing the watch and only awards experience.