Episode 6 I Believe the Children Are Our Future

Sam and Dean investigate a series of odd murders that strangely resemble fairy tales and urban legends. The brothers track down an 11-year-old boy named Jesse, and realize that whatever Jesse believes is coming true. Castiel appears again and tells Sam and Dean that Jesse is a serious threat and needs to be eliminated which deeply disturbers and divides them since it is against the Winchester brother's custom of killing a human.