Episode 18 of "Supernatural" saw Sam and Dean Winchester nearly cross over to the dark side in their hunt for the "Book of the Damn" in order to cure Dean from the Mark of Cain. This episode, "The Werther Project," continues this hunt for a cure but it also looks like the brothers will be putting their own lives in danger.

According to the official synopsis of the episode, Sam will learn that Magnus, a former Men of Letters, designed a mysterious magical box. Sam hopes that this box might help cure Dean of the Mark of Cain but what he doesn't suspect is that the box is riddled with deadly alarms that will put both his and Dean's lives in peril.

The synopsis does not mention either Charlie or Castriel so they might not be available to help the Winchester brothers this time. It is also possible that they may make an appearance but are simply not mentioned to keep the tensions rising until the episode finally airs on the CW Network.

Magnus' magical box is not the only focus of the episode, however, as the promotional trailer shows Sam telling Rowena "I'll kill Crowley." Killing Crowley, the King of Hell himself, might actually make things turn for the worst. As cited by VCPost, fans on Reddit have blown up the blogosphere with their rage against Sam's ill-conceived plan.

Dealing with Crowley is always exciting for the fans but the Mark of Cain storyline has been dragging on a little bit since it was first introduced in the tail-end of season 9. While it has given the cast an opportunity to successfully experiment and think outside the box, wrapping up the storyline may also lead to a better, more concise season 10 finale, especially with only four episodes to follow after "The Werther Project."

"Supernatural" season 10 episode 19 airs April 22, 2015.