After the bloody body count of the Saw movie franchise through versions one, two and three, you might be afraid the series has no one left to suffer a hideous and protracted death. Such fear fails to take into account the limitless resources of the human imagination for innovation, cruelty and making a string of sequels each creepier than the one previous. Saw IV's web of red-drenched mayhem draws a pair of FBI profilers into a deadly struggle of twisted gamesmanship. Spoiler alert? There will be pain.
