This spell can be cast on any spot the caster wishes. Should any living creature pass within 1 yard of it, the caster will be made aware that this has happened - even to the point of waking up if asleep at the time - no matter how far away the event takes place. The caster knows only that something has disturbed the spell and will not be aware of any other details. The caster may only have one such spell in existence at any one time. The spell lasts until the alarm has been triggered or until the caster casts another.