The puzzle behind the Mark of Cain may come into light next season, and it might be connected to Demon Dean's possession.

The tenth season of "Supernatural" will explore the role of the Mark of Cain in Demon Dean's current situation. It seems that the key to the mystery is with Crowley (Mark Sheppard). According to spoilers, Dean is far from being all right. CW Network released the synopsis of the second episode of the series entitled "Reichenbach," airing on Oct. 14.

Episode 2 shows that the Mark of Cain will be a source of problems. Crowley notes that Demon Dean (Jensen Ackles) is becoming more and more aggressive. Dean tells him that it is the side-effect of his possession, but Crowley knows better – that it is the Mark of Cain needing to be fed. What does "needing to be fed" mean? Does this mean that it is some kind of monster?

Previous spoilers deem Demon Dean as a menace, giving rise to speculations that he will be a villain next season. His brother, Sam, will chase after him and will try hard to find a cure for his current state, but the puzzling role of the Mark of Cain makes Demon Dean seem very dangerous.

The storyline about Demon Dean will be resolved in a span of at least three episodes. However, show runner Jeremy Carver said that fans will be entertained even after Dean goes back to normal. Just when everyone thinks that the case is resolved, twists and turns will happen unexpectedly, which is one of the main characteristics of the series.

Meanwhile, Sam (Jared Padalecki) is not the only one trailing behind Demon Dean. Cole (Travis Aaron Wade) is also after him. The latter blames Dean for his father's death and is now seeking revenge. The worst part is, Cole gets hold of Sam, takes him hostage, and tortures him in order to force him to reveal where Dean is.

On the other hand, Castiel (Mischa Collins) is busy with his own affairs. Hannah (Erica Carroll) sees that his grace is slowly fading. She makes a brave move to ask Metatron (Curtis Armstrong) for help.

"Supernatural" season 10 will be back on air on Oct. 7 on CW.