After we pulled off the road, the Librarian checked her phone and discovered that there was indeed a cache there named Isolation.
It turns out that it wasn't a cave but an isolation cell belonging to the jail on the other side of the fence and that many years ago this bunker was used as an isolation cell for disruptive inmates.
The idea of spending even 5 minutes in there gave me the creeps.
The cache instructions told us that the cache was not hidden inside the cell so we joined the other couple, climbed up the hill and started poking around.
After we'd looked for a few minutes the woman who was there originally pulled the cache page up on her phone to see if there were any clues to help us find it.
Instead she saw that the cache had been archived sometime in the previous five minutes.
I've never had that happen. One minute it was there and the next it was gone.
We climbed down off the hill just in time to see the prison guard walking towards us.
The couple started walking down the hill to talk to him and as they were walking the woman looked over her shoulder and yelled “Save yourselves!”
We weren't sure what was going to happen so we did. We jumped in the car and the Librarian peeled out of there, blew past the guard and we never looked back.
After we made our getaway we pulled the cache page up again and read that whichever jail official approved a geocache originally was no longer employed there and that no geocache would ever be approved along the jail perimeter.
It's too bad we didn't pay attention to this sign.
I really hope the folks who were talking to the guard talked their way out of trouble.