Too often, sequels are a disappointment, pointless endeavors beyond their ability to make a killing at the box-office. Commercially profitable or not, this kind of follow-ups offers diminishing returns to the audience and, in the worst cases, it can even turn us off to the material, making us forget why we liked it in the first place.

Personally, this is what I felt had happened to “Shrek”. I loved the original, but the so-so “Shrek 2” and the downright rotten “Shrek the Third” made it so that I didn’t care about spending any more time with the green ogre and his entourage. I walked into “Shrek Forever After” expecting another tired retread, coasting on pop culture references, familiar catchphrases and various other random gags, but devoid of a story truly worth telling and unable to make the characters feel fresh again.

Boy, was I wrong! As written by Darren Lemke & Josh Klausner and directed by Mike Mitchell, “Shrek Forever After” does what all best sequels do: remind us why we fell in love with these characters, while also finding different ways for them to interact in a new adventure.

So what did we like the most about “Shrek” back in 2001? As far as I’m concerned, it was finding out that the big scary ogre (Mike Myers) was really a softie on the inside, as he befriended Donkey (Eddie Murphy) and fell in love with Fiona (Cameron Diaz). We get all this from “Forever After” as well, the twist being that the bulk of the story takes place in a world where Shrek never stopped being that green monster living alone in a swamp. Remember in “Back to the Future Part II” when Marty McFly and Doc Brown found themselves in a sinister alternate timeline in which Biff was all-powerful? That’s kind of what happens here, with a bit of “It’s a Wonderful Life” thrown in, too.

Fed up with the routine of being married with children, annoyed with having become something of a celebrity and nostalgic of when he was feared, as an ogre damn well should be, thank you very much, Shrek accepts to sign a deal with Rumpelstiltskin (Walt Dohrn) so that he’ll get to experience his old life again for a day. Alas, there’s a catch, and our trumpet-eared hero will have to recreate relationships with this alternate reality’s versions of Fiona, Donkey and Puss ‘N Boots (Antonio Banderas) in order for things to return to normal.

As you can see, far from being another lazy sequel, “Shrek Forever After” dares to turn everything inside out, making Shrek an outsider again and forcing him to rise up to the occasion once more. This involves, amongst other things, a lot of awesome 3D action sequences, including clashes between Rumpelstiltskin’s army of flying broom-riding witches and the Ogre Resistance, which is led by Fiona, Warrior Princess! Add a lot of humor, just as much heart and plenty of fun music cues (The Carpenters, Beastie Boys, Lionel Richie, etc.), all of which are plot and character driven, and you get that rarest of things: a fourth episode in a film series that equals, possibly even surpasses the original.