From VtR (299):
Having tasted your blood, a Kindred has developed a strong connection to you as a result. Further, he has some vested interest seeing to your long-term survival. If you’re in danger, he knows about it, and he may come to you as quickly as possible.
Prerequisite: Ghoul or Human
Effect: If your character is in danger, her regnant senses it, and can spend a Willpower point to coincidentally arrive on the scene in time to save you.
How does this coincidental arrival work? Is it just plot armor, or is it magic, like Vitae teleporting through Invictus oaths? What happens if ghoul is threatened during day?