It is all the things Dean Winchester told his brother Sam about the time he spent in Hell. Time traveled differently there, 4 months on earth meant 40 years in there. In Hell, Dean was tortured very badly, day and night, until he would get all ripped. After ripping him completely, the demons who tortured him, would put him back as a whole only to start the torturing all over again. Alastair, a demon with whom Dean made a deal of his life for Sam's life a year before, would always tempt him to get off the hook, in return for his kindness. He wanted Dean to get with him and make the souls in Hell suffer. Dean, being the considerate soul, would always refuse his offer. But at last, after 30 years of suffering, he finally gives in. It was said that Lucifer, the Devil, was bound by 66 seals in Hell. The first seal could only break if the most righteous man tortures souls in Hell, and only that man could stop Lucifer from destroying the world i.e. Apocalypse.