Ep 13. Unforgiven

In Supernatural season 6 episode 13, entitled "Unforgiven," Sam and Dean revisit a case from their past that they had thought was solved years ago. They discover that a man named Roy, who they had previously believed to be the killer behind a series of crimes, is, in fact, innocent, and the real killer is still out there.

Meanwhile, Sam finds himself haunted by memories of a time when he was possessed by a demon and committed terrible deeds. As the brothers investigate the current case and try to track down the real killer, they are also forced to confront Sam's past and the question of whether he can ever truly be forgiven for his actions.

The episode explores themes of guilt, redemption, and the struggle to move forward from one's past mistakes. Sam's journey in particular is a major focus, as he grapples with the weight of his guilt and the fear that he may never be able to fully make amends for his past actions.

Throughout the episode, the tension builds as the brothers race against time to catch the real killer and clear Roy's name before he's executed for crimes he didn't commit. The identity of the real killer remains a mystery until the very end, with several surprises and twists along the way.

Overall, "Unforgiven" is a gripping and emotional episode that explores some of the darker aspects of Sam and Dean's pasts while also delivering plenty of suspense and action. It's a standout installment in an already impressive season of Supernatural.