Witch's Fire — Beverly Butler

When firelight reflects in a windowpane, they call it witch's fire. There may be some truth in those words.

Kirsty Hamilton has had to except a lot of hardship -- life in a wheelchair, her father's new wife, and moving far from anything familiar. As if that's not bad enough, her bratty stepsister, Pam, is convinced that a witch is trying to take possession of their house. Kirsty thinks Pam is crazy -- until the living room window reflects a door that doesn't exist, the cat hisses at things that aren't there, and Pam's boundless energy begins to drain away.

As Pam gets weaker, Kirsty begins to realize the danger they're in, and suddenly their fate depends on whether Kirsty can resist the pull of another world -- or whether she even wants to.