Zero.

You can try to count down from one hundred by sevens, but you can't, not really. You stop at two, or you go too far and end up with a negative number. The ritual is broken.

What seemed to Celia like a green trap looks like paradise to me. You reach a limit in this world, and if you're lucky, you find a door.

I made a promise, written in mud, long ago. A trade: me for her. I didn't remember. I do now. It's time that I fulfilled it.

I'm leaving now. I don't think I'll be back.