Sacred guardian

From Ardrana

By use of the sacred guardian spell, a priest becomes instantly aware when the recipient of the spell is in danger, regardless of the distance between the priest and the recipient. The recipient may be on a different plane of existence than the priest. If the priest is powerful enough, he receives a mental image of the endangered person's situation. At no time, however, does the priest know the person's location through the use of this spell.

Note: This spell originally appeared in this form in the Tome of Magic for the AD&D game from TSR. Their use here is for the purposes of providing context for the campaign only.