A screening of the first five minutes of the CW show's season 4 opener [reveals: ] Since Dean was left in hell the last time we saw him (after a rather messy and tragic exit from this mortal plane) seeing him literally crawling out of the grave was both heartening and terrifying. A newspaper in an abandoned gas station nearby tells both Dean and the audience that it's four months later, but the scene ended (with a mysterious force that knocks Dean out) before anything else could be revealed. Source: Entertainment Weekly

Specifically, find out why insiders are calling it "the most pivotal episode of Supernatural ever."