why is there no search engine in the fiction archive?

How can i search stories based on tags that are not in the index?

I believe the answer is that it is behind a password wall, and unless a mechanism was installed to process that search within the server (IE not through some sort of Google/Bing/Etc. searches) it would remain that way. It has no keyword search either, I'm speculating for similar reasons.

Keep in mind, the archive is run by volunteers and the servers paid for with donations. I'm sure the moderators would love to offer that level of service in the story archive, but do not as it would take someone with programming skills beyond their abilities to make it happen.

If any of what I said above is not the case, I welcome the folks in charge of the story archive to correct my statements.

The next step is to decide what is happening in the story you wish to find and select the tag that best describes what you are looking for based on other things in the story. It would take a while, but it might work.