"A ghost who can only appear in a particular environment. I died ages ago. Who could really live for over a thousand years?" Doppelgänger said frankly. "Hmm, it's like the magical portraits in Hogwarts Castle. They can only move around inside paintings; once they leave, they turn into a wisp of smoke and disperse. I'm the same. Only here, in the world of books, can I pop out and meet you. But-even that's temporary. We'll soon have to say goodbye forever, Brian. I'm about to be gone. Poof, rather like the gas that escapes when you open a bottle of wine."
Brian froze, not because Doppelgänger was dead, but because Doppelgänger, in his ghostly state, was about to fade away. The deeper his understanding of magic grew, the more keenly he felt the limits of human life. Time, so often praised, never showed mercy when it brought down its blade. When he first met Doppelgänger, he had felt as though he were seeing someone from one of the magical portraits in the Castle-a ghost in a painting. That was a good explanation, but magical portraits lasted a long time. Their frames allowed them to escape time's grasp. Since Doppelgänger's present state resembled theirs, why did he suddenly have to say goodbye?
"Why? Your condition is clearly stable," Brian asked, bewildered.
Doppelgänger stopped laughing and continued, "Cheer up, old pal, because I'm about to fulfill the obsession that kept me here. Every ghost remains in this world because of an obsession. Whatever happens later, it must begin with an obsession-perhaps some unfinished business, perhaps a few people they can't forget, or simply a desire to live.
"If that desire is strong enough, it becomes a wish. Wishes are immensely precious, and their power always exceeds our imagination. That magic, capable of