His little secret is out and so is the latest “Dexter” promo video. Now needless to say if you’re not all up to date with the series, you probably don’t want to read on or watch the promo because there are some major spoilers afoot, okay? Right now we’ve got that out of the way, who else can’t wait for “Dexter” to return September 30 on Showtime? Now that Deb has seen his dark passenger in action, it looks like it’s going to be one stress filled season. Check out the latest promo below.