Stealing a page from meta-universe science fiction - and maybe from the desperate scribes at Lost - Shrek Forever After, also known as Shrek: The Final Chapter (make 'em promise!), also known as Shrek 4, finds the big green ogre venturing into an alternate reality where the scenarios played out in previous Shreks have mostly been undone.

Donkey as Shrek's best friend? Nope, they're strangers.

Fiona as Shrek's one true love and spouse? Forget it. She's the leader of an ogre resistance movement, decked out in warrior gear and built like an R. Crumb dream girl.

The undoing comes courtesy of Rumpelstiltskin, the mad magic barterer of storybookdom, who, in Shrek Forever After, offers DreamWorks Animation's box-office behemoth a deal: In exchange for a day in which Shrek can revert to his wild and beastly ways, the ogre must sign away a day from his childhood. Unbeknownst to Shrek, however, the one Rumpelstiltskin chooses is the day Shrek was born. Take that day away and Shrek doesn't exist. Or, he exists only for the 24 hours that he's signed the contract for, and then he'll disappear into a black hole of nothingness.

As Rumpelstiltskin, who has become the tyrant king of the land, observes, "How's that for a metaphysical paradox?"

And how's that for a plot device that (1) gets Shrek (the voice of Mike Myers) out of the married-with-children drudgery that has become his life, (2) enables him to reaffirm his love for Fiona (Cameron Diaz) by having to woo her all over again and (3) allows the writers and director to throw The Wizard of Oz (a squadron of Margaret Hamilton-esque witches) into the mash-up of Grimm, Andersen, and other fairy tales that has been the Shrek series' stock and trade. In addition to Puss in Boots, living very large (and voiced by Antonio Banderas), this time the identifiable inhabitants of Far Far Away include the Three Little Pigs, the Three Blind Mice, Pinocchio, and the Pied Piper.

More a slick product than a piece of soulful entertainment, and available for consumption in 2-D and 3-D formats, Shrek Forever After has moments of visual dazzle - the aerial battle between the witches and Shrek and company inside Rumpelstiltskin's grandly made-over castle is pretty spectacular - and the sour scalawag Rumpel (Walt Dohrn), preening and scheming, makes for an amusingly malevolent villain. But the quick wit and multitiered pop-culture referencing that made the inaugural Shrek so much fun doesn't feel so quick or multi almost a decade down the line.

Shrek Forever After is - forgive me - mediogre at best.EndText

Contact movie critic Steven Rea at 215-854-5629 or srea@phillynews.com. Read his blog, "On Movies Online," at http://www.philly.com/philly/blogs/onmovies/.