After this discussion, I thought I'd try starting a new story under "And now for something completely different." I wanted an object that was a little less powerful than the stone, and that might create some awkward situations without complete recklessness on Jon's or Karyn's part. I kept Jon and Karyn though.
And in looking for an object to replace the stone, I certainly didn't rip one off from a certain manga/anime series. Nope. Nothing to see here. Frankly I resent the implication.
Fans of Death Note will notice I added rules for compulsory use of the book (but I even stole that idea, in a way). Like I said, I wanted to give them a little push.