Michael C. Hall

Almost no one who has learned Dexter's secret has lived to tell about it. (See: Lila, Travis, Miguel Prado, etc.)

Now that Deb (Jennifer Carpenter) has learned her brother is a serial killer, could she be the next person to fall victim to his hobby on Dexter? The new trailer for the upcoming season seems to indicate that she really needs to watch her back.

Dexter: Now that Deb knows, it's the beginning of the end

Although she lets Dexter (Michael C. Hall) walk off a free man after he killed Travis (Colin Hanks), she's definitely starting to suspect that it wasn't just a one-time thing. But can she really accept that her brother is a full-blown serial killer? Judging by the punch Deb lays on Dex in the video, tensions are running high between the siblings. Add to that the similarities she sees between Dexter's church crime scene and that of the Ice Truck Killer's, and it's no wonder Dex is driven to take action against his sister. On top of all that, LaGuerta (Lauren Velez) is breathing down his neck as well. To find out why, check out the spoilery Season 7 promo:

Dexter returns Sunday, Sept. 30 at 9/8c on Showtime.