"It’s going to happen," said a voice.

"What’s going to happen?" Laura asked before she realized that the voice had spoken inside her, not outside in the room.

It’s a warning, Laura thought with a sinking heart. She had had them before, not often, but in such a way that she had never forgotten them. It always seemed to her afterwards that, once she had been warned, she should be able to do something to alter things, but the warning always turned out to be beyond her control. The warning was simply so that she could prepare to be strong about something.

The Changeover by Margaret Mahy —