Despite Dean's directive to forget about looking for a cure for the Mark of Cain, Sam continues to do research. Dean suspects Sam is hiding something but decides to focus on a new murder case where they run into Cole. The three team up and learn a Khan worm is infecting men and turning them into murderers. Unfortunately, the worm makes its way into Cole.
Comments
That "Dean-o" and "Sammy boy" heard from Cole was weird... like they knew eachother forever
Entertaining "classic" episode.