On the season premiere of Supernatural…
One year later and Dean is back from Purgatory, although he brought a "friend," Benny, with him. Castiel didn't make it out.
Sam had been seeing a girl after meeting her at a vet's office after he hit a dog. He gave up hunting.
The brothers reunite and learn that Kevin managed to escape Crowley's grasp.
They discover that there is another word of God all about demons. Not only does Kevin know how to kill them, but there is a way to shut the gates of Hell forever.
Crowley tries to convince Kevin to give it up for his girlfriend, who is possessed by a demon. After Crowley is tricked, he kills Kevin's girlfriend.
Sam, Dean, and Kevin escape.
Dean gets a phone call from Benny telling him that they'll keep in contact.