So, my DnD5 group is breaking up in two weeks. Two of our regular players are moving out of town, and honestly, I'll be skipping country soon, I've already contacted people. Trudeau scares the shit out of me.

I think we need a sendoff. A shitshow or a summary resolution that will stick with us for the rest of our lives. The rest of the group is frankly too old-fashioned to teleconference games.

To maintain consistency, We're basically trying to rescue someone or something from evil miners or something. I got too drunk to remember exactly what, but we're underground, but not underdark underground. Is there anything you guys think would be entertaining and tie this thing off that would take about 4 hours (mean time to drunken incoherency)?

Optional, maybe useful information:
The players:
Paladin of Libertarianism
Runaway-Prince Monk
Sniper Ayn Rand Rogue
Harem-building Wizard who wants to marry into royalty, "secretly" possessed by a fragment of Vecna's will
Naive Oathbreaker Drug-Dealer Druid

Average group alignment, 0.2L, 0.8G

Open plot hooks:
There's a Lich that let us get off way too easy, monologuing like a scooby-doo villain.
The wizard seduced [not queen elsa] away from an ancient white dragon. Dragon remains at large.
If the goblins or the mind flayers ever figure out what the druid did, there's be assassins on her for the rest of her natural life. Same for the king of the realm of which we are knights and the whole party. Same for the cult of bahamut and the rogue.
The rogue's oathbow is currently sworn to kill the paladin.