Is there a published campaign where a missing artifact or a relic is creating trouble by its absence?

Question

I already wrote months ago a question about linking Lost Mine of Phandelver to another published module. By then, I hadn't yet bought the starter set and hadn't even GM'd.

I now have GM'd through the first chapter of the starter set campaign, and I really love it. I'm now sure that I'd like to buy other modules to follow on after LMOP.

In the previously linked question, Storm King's Thunder was the most cited module, and it seems pretty interesting. It was the first module I was thinking about to buy after the starter set campaign is over.
But now that I have started to play with some friends, one came with an interesting background :
His character is a monk (a woman, can't find the word for it) that before joining the group for their quest in LMOP, was guarding a temple where a powerful artifact lied, the kind that could create war over it. His character can't speak about this artifact, as it could create trouble.

I really like this background (found on aidedd.fr, a french site with a lot of translated data from the basic rules), and I'd like to use it as a plot hook for a module to string after LMOP.

So, I was wondering if there is a published module where there's a missing artifact/relic which is creating trouble by its absence.

The artifact doesn't need to be found by characters at the beginning of the module, it can even be held by the BBG. I would handwave something to link it, like if the BBG have to get it, then he may steal it in the temple or something alike.

I'd like only published modules.
If there's a module with a missing, important item, even if it's less powerful than an artifact, it's worth mentioning it too.

Answer 1

There are several...though they are not 'Artifacts' in the sense of being an Artifact-tier magic item, but they are unique items of significant power and importance that are causing problems and the fact that the 'wrong people' have them is central to the story, and having them be an item that used to be secured and has now been stolen is a pretty easy adjustment to make.

As requested in a comment, I'm also including the locations where these campaigns take place.

Naturally, spoilers abound. Proceed with caution.

Tyranny of Dragons

The Tyranny of Dragons modules (Hoard of the Dragon Queen and Rise of Tiamat) revolve around the use of 'Dragon Masks' that give their wearer influence over chromatic dragons, and someone seeking to unite all 5 of the masks to summon the evil dragon-god Tiamat into the world. The Monastery could have been guarding one of them.
This campaign ranges all up and down the Sword Coast from Neverwinter to south of Baldur's Gate--it technically starts in Greenest, a town just south of Baldur's Gate, but relocating that town would not be too difficult.

Waterdeep: Dragon Heist

The Stone of Golorr is a magical item central to this adventure that is used to obscure secrets, and also contains knowledge of a vast array of things probably-better-left-unknown. It's also evil and sentient. It was acquired by Open Lord Dagult Neverember for his own purposes--but could easily have been held by the Monastery beforehand
This campaign takes place entirely within the city of Waterdeep.

Princes of the Apocalypse

This adventure features 4 Magical Weapons of significant power and danger--each capable of creating Weapons of Mass Destruction when used in the right place and the right way, and each also usable as a key to free their respective Lord of Elemental Evil (note: any one of them being freed is a world-ending catastrophe). Note: these weapons are also corruptive in nature, drawing out negative qualities in those who wield them. Again, one or more of these weapons could easily have been held by the Monastery.
This campaign is geographically the closest to the events of LMOP, taking place in the Dessarin Valley, which is just south of Triboar--only a few days' travel from Phandalin

Answer 2

Yes, there is one in a published module

In Tomb of Annihilation (ToA), there is

The Ring of Winter

That item is carried by an NPC and other NPC's are searching for it. (FWIW, I think it will dovetail into SKT nicely - but that's personal opinion). It has potential world-wide implication if certain parties get their hands on it. It is "missing" in the sense that two groups of NPCs want it, and another NPC (who is nearly impossible to find except by random encounter) has it in their possession.

It is a very powerful item to the extent that in Adventurer's League, during public play, that item will be confiscated/removed from a player who ends up with it on their character sheet if they end up with it during play. We have a Q&A on that here. Caution: there are spoilers.

The trouble with it being absent.

For one thing, it is mentioned in the Storm King's Thunder adventure as being absent in the introduction. Its absence informs a piece of the back story for a key faction in the adventure: the Frost Giants.

In the introduction, the motivations for the Frost Giant Jarl (king) is shows that recovery of the Ring of Winter is one of his prime objectives. He wants that artifact to bring back a kind of Ice Age in the North. His problem is that the means he has used to track it down - using a drop of blood from the last person known to have it - has created a red herring. His agents are tracking down relatives of the person who has it, not the person themselves. In other words, based on the lore up to the time of SKT, the Jarl will never find it.

ToA was published after the SKT adventure, which changes the lore(continuity) and thus the chances of the artifact being found, as well as the means by which it may be found.

Our ToA group ran into a two powerful groups of NPCs (well, more powerful than our party by quite a bit as it turned out) who were looking for that item specifically. We had to use our wits to get out of those encounters without a TPK: the power imbalance was that bad.

The trouble in a larger scale is that a group of dangerous and powerful NPCs is running amok in a part of the world that they don't normally visit. The mission that led to us encountering them was that their presence had severely disrupted trade on the eastern coast of Chult. (Among other things)

I am leery of saying more given the spoilerish nature of the reveal.

Answer 3

In Curse of Strahd, there are 3 missing

magical "seeds" (green glowing rocks) that allow a vineyard to grow grapes.

Two of them are in known locations in the valley, while the third is long ago lost and unknown.

While not nearly as powerful as what you might be looking for, it should be easy to modify to give them additional powers or importance.

Answer 4

Curse of Strahd also has the missing item

bones of st andral

These are a timed item, where if the players ignore the quest then the area they used to protect has an event where it is attacked. Not quite the same level you are looking for, but something providing protection from evil to a large area is often a good questline if you need to save it/recapture it.