I think before going to the asylum I may have killed Cayia, because I have since agreed to go with Saemon but when I go to get the horn at her house, at night, there is no one there and there is nothing on the table, chest, or armoir. Help please!!

You must go there by night to find her and the horn.
Perhaps you went by day?

<font color = "lightgreen">If all else fails, you could create the horn through CLUAConsole; its code is "misc9g".

Do you, um, frequently kill people for little or no reason? :D </font color>

The first time I went it was 4am and she wasn't there. I restored my previous save and this time left Spellhold 'faster.' I got there 3am, and she was there.

-Colin.

Just sleep out the duration until dark again...she'll be there with her lover...