By the time you get to the fourth film, the script is defined by desperation. You reach for the start-all-over-origins saga, the mentor-the-young-apprentice-and-pass-the-torch trick, or the amnesia gimmick.

　　 If you're really desperate, there's one more: the alternative universe.

　　 Shrek, the green ogre with a Scottish accent, is back for the fourth, and we're told, final time. (Are you buying that? Me neither.) The creative team at DreamWorks animation chose the alternative universe track to freshen up "Shrek Forever After."

　　 Surprisingly, it works.

　　 Shrek (Mike Myers) is bored and beaten down by the tedium of married life and raising a trio of little ogres. During an especially grouch-inducing day he has one of those George Bailey, I-don't-want-this-crummy-life moments, and just as in "It's a Wonderful Life," he gets his wish, or at least is devilishly tricked by ratty little Rumpelstiltskin.

　　 Suddenly Shrek sees a world where he never met Fiona (Cameron Diaz), Donkey (Eddie Murphy),（英文影评） or Puss in Boots (Antonio Banderas). They all exist, but in a Far Far Away in which evil rules. Shrek has 24 hours to reconnect with his friends, save the day, and get his old life back. Can he do it?

　　 "Shrek Forever After" is a trifle of a film. Short, sweet, funny, and completely entertaining. It is more sharply made than Nos. 3 and 2.

　　 I would rank this as the second-best "Shrek," behind the wonderful original. But the general public would vote otherwise. "Shrek 2" is the fifth top-grossing film of all time.

　　 The version I saw was in 3-D. It will also be in theaters in 2-D. As with many films this summer, and especially on the heels of the outrageous success of "Avatar," the major studios have learned that people will pay an extra $3 or so for the privilege of seeing the wonders of 3-D.

　　 This is going to knock me off the DreamWorks Christmas list, but there's no compelling reason to see "Shrek Forever After" in 3-D.

　　 Yes, some moments have that HD, you're-in-the-picture appeal, and a few objects fly in your face, but I don't see enough visual wizardry to drive the pumped-up ticket prices. I can't see how the fourth "Shrek" wouldn't be just as enjoyable in two dimensions as in three.