That sounds like a possibility. However, the Manhattan Project didn't get started until 1942. Still, anything that features Nazi villains is a good thing.
I was thinking more along the lines of an ancient Chinese herb. One the Yellow Emperor himself declared utterly anathema, and ordered destroyed. The herb's active ingredient totally destroys a person's will, making him the slave of whoever has enough moxie to give him orders.
The scion of an ancient mandarin family has isolated the active ingredient, and turned it into an aerosol. "Sauron's" plan is to spread it over the world by means of the jet stream, while he and a few advisors stay safe inside a hermetically sealed room. But first they need to get it out of the safe. That's where the ring comes in.
Along with a complicated series of locks to be opened by key and combination, the ring must be placed in a small, ring-shaped depression. Once that is done the safe opens and the "essence" can be removed.
As long as the "essence" is in existence, humanity is in peril. Once our heroes learn about it, they need to find a way to destroy it. And to destroy it they have to get ahold of it.
That is where the ring comes in. They need to take the ring into "Sauron's" lair and use it to access the "essence".
"Sauron" (let's call him Wing Lu) is a handsome man with more than his share of charm. He can also be a cold, vicious fellow when angered. Though even then he never loses control. He is also passionate about the Byzantine Empire, and a great admirer of the Emperor Justinian. He can go on for hours about his favorite subject. Furthermore, Wing Lu likes to think of himself as the reincarnation of the Byzantine general, Belasarius.
(I do hope somebody is compiling all this stuff together, 'cuz I'm pulling all this out of thin air.

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