This is one of those really dark episodes that show the range of Supernatural. Absolutely devoid of comedy, this episode really cuts to the heart of what being in Hell did to Dean, and shows what the show is really made of.

The CW Network's Supernatural Episode 416

The episode opens with Castiel investigating the murder scene of a fellow angel. Her wings are scorched into the earth, while cars are flipped on-end. Castiel and Uriel come to find Dean and force him to torture the captured demon Alastair for information. Dean refuses, saying he can't become what he was in Hell, even if it means getting back at the demon who tortured him in the pit. The angels tell him he has no choice, and Dean gets to work.

Sam contacts Ruby for help, and she tells him where Dean is before slicing open her arm and letting Sam drink her blood, revealing the source of Sam's increased demonic abilities.