Det. Nick Knight: You have to understand that every drop of blood has your whole life in it. It's just not our food. It's the way we feel life. Imagine if you could know someone's soul just by sharing blood. Everything you know, everything you are, transformed into touch and taste. Imagine the temptation to take just one sip. One sip and then another and another, to take them inside you and know every secret, to let them know yours, to be them. That's why it's such a tough habit to break.