Sam continues to try to save Dean from the Mark of Cain. Realizing that Dean's antics are causing problems for him in hell, Crowley seeks help from a reluctant Castiel.

After the massacre at the ranch, Dean, Sam, and Castiel double their efforts to find a cure for the Mark of Cain. Desperate, Castiel comes up with an idea that Sam deems the single worst idea he's ever heard. Meanwhile, Rowena continues to plot against Crowley.