Unobtanium Factory

[sabelo2000]

The Situation:

The PCs, as a small recon unit for their army, have tracked the source of the enemy army's new weapon (zekelhut inevitables, in this case) to a factory deep in enemy territory. The factory is too well-protected to assault directly, and the Zekelhuts too numerous to wipe out piecemeal.

The factory's critical weakness is the limited supply of some exotic material, which is necessary for construction of the Zekelhuts and is obtained through some ridiculously complicated--yet somehow realistic--supply chain.

So here's the question: what's a good Unobtanium supply that my PCs can interrupt and shut down this factory? I'm trying to think of something that's not generally available in a normal Material Plane world (mithral, for instance, is too common) but not ridiculously rare (distilled souls of alternate-universe Harry Potter characters, for instance). Also, a previous quest involved thwarting the villain's plot by shutting down an interdimensional portal, so I'm trying to stay away from that solution again (I wrote the adventure long before Oblivion, and it seemed creative at the time).

[Arcanist]

Starmetal.

[Xefas]

The creation of Orichalcum requires a complex and dangerous process, involving the mixture of molten gold and silver with the fresh magma of an active volcano, inside a crucible positioned over said volcano, and under an array of complicated, delicate, and precisely calibrated alchemical mirrors that concentrate, purify, and focus sunlight into the final solution.

1) The mirrors need to be replaced every so often. There are extremely few combination alchemist/glassblowers in the world capable of making them. Disrupting the transportation of the mirrors, convincing the alchemist to discontinue their creation, or outright killing him, would end the Orichalcum process.

2) Orichalcum comes in large batches, which each take a long time to make. Disrupting the (likely heavily guarded and/or secret) shipment itself may suffice.

3) Handling molten metals inside a volcano is hazardous work. Either the laborers are utilizing some kind of magical item to aid in the process (amulets of fire resistance, for instance), in which case the abduction of these items would halt production, or perhaps they are enlisting the aid of extraplanar help - Fire Mephits, Fire Elementals, Devils, or the like. In the latter case, banishing would work, and in both cases, bribery or (if their working conditions are poor) inciting insurrection is a viable strategy.

4) Smashing the whole facility into uselessness, and heaving the remains into the bubbling lava isn't very subtle, and probably the most difficult. But makes for an okay Plan D.

[JeminiZero]

Another possibility: The bottom of the ocean, where the immense water pressure is required to forge the unobtainium (possible riverine from Stormwrack). The plane of water won't work since it has no true gravity and no water pressure.

You could also combine it with the volcano idea for a deep underwater volcano or something.

[Killer Angel]

When someone bathes in the Lethe river, it loses all its memories and part of its soul... those things condensate in pearls and stony fragments that cover the river's bed.
Fiends collect those "gems", amassing them in treasure chambers for various uses. One of those uses, is to act as components for the process that imbues mechanical constructs with a basic "soul".

The group must find the connections and interrupt the chain of supply.

[CTrees]

A nonaton modron has been captured. His essence is slowly being siphoned off to provide the motive power for the inevitables. There is a massive effort in place simply to keep up the wards hiding the nonaton from divination (for instance, lead walls may block scrying, but they don't stop Contact Other Plane), to stop the nonatron from simply dying, and to actually drain its essence. All of these efforts require teams of specialists.

[Andorax]

The construction of the Zekelhuts is overseen by a specialist who has a crucial role in the final activation of each one. Take out the key "scientist" or convince him to change sides and you stop the production.

Is the enemy army holding his family hostage somewhere?

[sabelo2000]

Thanks all for the suggestions!

[Airanath]

I particularly like the poor work conditions thing, toss the law enforcong lawyer inevitables into the zelekuts because thier creator is exploiting the contract.