That was also the last day I saw Fé. She wasn't pleased when we took in Sugar for fostering, but they were starting to adapt to each other, so I don't think she left in a huff. She was an indoor/outdoor cat when we adopted her last fall and I couldn't see trying to keep her indoors, especially since I always considered our neighborhood very safe, facing onto the golf course instead of the street. But it appears that wherever the Cat Man's cats went, Fé went too.
Since then, I have only allowed Sugar into the patio when I can be there to keep an eye on her. The Capt and I still sometimes walk around the neighborhood calling Fé, hoping she'll turn up, but now it's been almost a week and we are discouraged. She was only with us for about eight months, but she was so much a part of our lives, it will take a while to get used to not seeing her perched by the front door, surveying her territory.