Ours are indoor cats too, Boo (poetry forsooth) and it beats me how in the name of the wee man they can manage to disappear within the confines of the house! We lost Molly for hours (see avatar that's her) and combed the house, we found her eventually under the bookcase - where we'd already looked as it was always a favourite hiding place of hers. I think Scotty used to beam them somewhere...........