The Vampire Diaries, Season 4

Katherine:
I'm perfectly aware that tombstone isn't just a hunk of rock.

Bonnie:
No kidding.

Katherine:
And it got me thinking, all big spells require a source of power, a recurring element like a full moon, a comet. But that tombstone is filled with the blood of your ancient reflective Katsooyay or whatever.

Bonnie:
Qetsiyah.

Katherine:
She was powerful enough to create the other side. So maybe, if you have her blood, you don't need a full moon to drop the veil. Maybe you can do it whenever you want. The thing I can't figure out is why do you want to drop the veil at all?

Bonnie:
I have my reasons.

Katherine:
And again, I ask, what's in it for me?

Bonnie:
You'll get the one thing you want most in this world-- freedom, survival. Never having to run from anyone again. Once I've dropped the veil, I can speak to Qetsiyah. She created the spell that made Silas truly immortal, invulnerable to any weapon. You'd like that for yourself, wouldn't you? I can give it to you.

Katherine:
Bonnie Bennett, we have a deal.