Supernatural (Season 3)

 The season mainly focuses on trying to save Dean from his deal and tracking down the demons that were released from the gate. Along the way, the brothers meet Ruby, a "good" demon, who has an interest in Sam and claims to be able to help save Dean. Also, they meet Bela Talbot, an acquirer and seller of occult objects, who is constantly a thorn in their side. The brothers eventually learn from Bela which demon holds Dean's contract: a powerful demon named Lilith. Lilith takes Bela's soul after her contract expires, but not before she warns Sam and Dean. The brothers, along with Ruby, track Lilith down and attempt to kill her. Lilith is unable to stop Sam on account of his mysterious abilities; however, Dean's contract expires and his soul is taken to Hell.