I have two versions of this book. The one at Royal Roads is the original. The one at Scribble Hub has a relationship component and better character development. Nothing X rated.

Royal Roads original version:

https://www.royalroad.com/fiction/115979/the-last-ring

Scribble Hub relationship version:

https://www.scribblehub.com/series/1661925/the-last-ring/

Synopsis:

When Harmony moves to the outskirts of a small town near the redwoods, she discovers the existence of a massive stone ring of unknown origin. The appearance of an enigmatic woman of indeterminable age only adds to the mystery as she exhibits unusual abilities.