Dexter season 4. I was planning to watch this just 2 eps a week, but I've raced through it in barely a week (last two eps tonight!). Just too gripping and addictive. I didn't think I'd ever be able to take John Lithgow seriously again after 3rd Rock from the Sun
, but he's terrifying as the husband, father and "pillar of the community" who's living a double life as serial killer "Trinity", who's been endlessly recreating the deaths of his own family as a child on innocent people for the last 30 years.
So many twists and shocks along the way. Great season so far, possibly the best yet.