She let the more painful past lie and concentrated on the disturbing present. "Hm. Some of the materials on protection against malevolent spirits and such suggest binding circles, and wards... I suppose walls wouldn't count as barriers unless the space inside is warded. They probably won't kindly wait outside while we ward against their entry, though. And I can't remember the exact diagram for the warding circle - I'd have to look it up again. But we could try that, if you like..."