Legal Question in Wills and Trusts in California

Your post is a little vague. Do you mean that there is a holder of a promissory note, that has died? Are you saying that this promissory note was secured by a deed of trust, or other security instrument on real property? Are you thinking that the deed of trust just goes away?

California adopts the rule that a party who owns real property cannot quiet title to a mortgage or deed of trust, without paying off the debt. There are several exceptions, but I can't tell whether they apply given the vagueness of your post.

There are always living heirs. If you have to go all the way back up the family tree to Eve and back down, you eventually find a living relation of some distant connection, and they will have rights of inheritance.