Cas was more than happy to give them a little blood before jetting off to parts unknown. They now needed the blood of Crowley and the blood of an alpha. Crowley was being a little stingy with the plasma until they brothers got all the other parts that they need.
Meanwhile, Dick kidnapped the scribe of the Word of God and after providing a very nice letter of recommendation to Princeton and threatening to kill his mom, got the translation of the tablet. He sends Edgar to get the vampire alpha and arrived just a bit later than the Winchesters.
It turns out Roman purchased Sucrocorp, which provides most of the world’s corn syrup. He adds his turducken mix to it and now the entire population acts liked stoned zombies, minus the eating of human flesh. Another side effect is that any creature be it vampire, werewolf, etc. that feeds on the stoner zombies is poisoned and dies.
After the alpha realizes the whole thing was the plan of the leviathan, he was more than happy to provide a little blood. The last scene was Dick conjuring up Crowley and asking him to sit down. It looks like the brothers are going to have a little difficulty in getting that last bit of blood. Adding to the problem is Bobby possessed a maid and took the flask with him as he went on a one-ghost manhunt for Dick.
Whew, can you tell the season is ending?