I've done some shady stuff, but I am not doing this.

To what action is Dean referring with this quote? Viewers will need to tune in to Supernatural on Friday and find out. They can get a sneak peek at the upcoming installment now:

[video url="http://www.tvfanatic.com/videos/all-dogs-go-to-heaven-promo/" title="All Dogs Go to Heaven Promo"] [/video]

On the episode "All Dogs Go to Heaven," the siblings look into a killing that turns out to be the work of a skinwalker. He informs the brothers of an Alpha skinwalker that has created sleeper cells intent on murdering their families.

How can Sam and Dean prevent countless deaths? Kill the Alpha.

Return to TV Fanatic for a full review soon after this episode ends and visit our Supernatural spoilers section for a broader view of what's ahead this season.

Matt Richenthal is the Editor in Chief of TV Fanatic. Follow him on Twitter and on Google+.