The first episode of the tenth season will mark the 200th episode of the whole "Supernatural" series and will supposedly be a musical, featuring both original and cover songs. It is still unknown whether the actors playing the Winchesters, Jared Palacki (Sam) and Jensen Ackles (Dean) will be singing in the musical episode.
Season 9 ended with Dean becoming a demon due to the influence of the Mark of Cain. This was after he was fatally wounded and promptly dies from his wounds after his fight with the angel Metatron.
After Dean's death, Sam attempts to summon Crowley to make a deal and resurrect him but Crowley has already visited Dean and reveals that the Mark of Cain won't let go of him, hence his conversion into a demon.
The season 9 finale ends there and has left fans at the edge of their seats, eagerly wanting to know what happens next.
Now that Dean is a demon, Crowley finally has a weapon he can use against Sam. Sam, unable to destroy is brother (and not knowing Crowley is behind this) won't be able to retaliate until episode three. At that point, he finds out that Crowley is behind all of this and gets mad at him, not Dean.
Palacki, who plays Sam, revealed to E! Online about him not knowing Dean's demon status at the beginning of the season and his supposed hate towards Crowley after finding out.
"He doesn't know that he's a demon at the beginning of season 10. But when he finds out his brother isn't just missing, he's a demon, it doesn't piss him off. He doesn't think Dean did it on purpose or anything. He gets pissed off at Crowley instead," Palacki says.
It is also unlikely they will be able to kill the King of Hell in season 10. Also, it would seem that Dean is actually enjoying being a demon, after his unsavory experiences in the past seasons.
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