Upon its theatrical release in 2003, Finding Nemo became one of the highest grossing films of all time. At most animation studios, that would have been reason enough to quickly proceed with a sequel. But back then, Pixar Animation Studios was all about originality and creating new worlds. Since being acquired by Disney in 2006, Pixar has changed a little. They're still capable of wowing with imaginative new tales like Inside Out. But they've become more aware and accepting of the realities of business. After Toy Story 3 joined the then-exclusive billion dollar worldwide movie club in 2010 without any dip in the studio's integrity and standards, who could object to sequels and prequels becoming a staple of Pixar output? Certainly not Disney shareholders and neither could those who simply considered themselves fans of the most decorated and successful animation house of modern times.

After a lackluster Cars sequel, a fine but unextraordinary Monsters, Inc. prequel, and last year's oppositely received original movies, Pixar returns to the universe of what was once their biggest blockbuster ever. The title and trailers for Finding Dory have not inspired the greatest amount of hope. A similar plot with one twist was the kind of thing Disney did during their lamentable direct-to-video sequel craze that coincided with Pixar's peak creativity. Still, you have to imagine Pixar would try to protect and honor the legacy of one of their most popular films both in the interest of their brand and out of duty to the generation for whom it was one of the most-seen and best-loved films. Some of that generation is already old enough to have kids of their own who are sure to be part of the audience for a follow-up whose built-in appeal overshadows any concerns of narrative inessentiality.

Gladly, Finding Dory is decidedly not a remake of the original film with Dory as the missing fish. We open with the blue tang fish a doe-eyed child living happily with her parents Charlie (Eugene Levy) and Jenny (Diane Keaton). Those parents try to help her overcome the short-term memory loss with which she was born. But she soon gets separated from them in a sequence that will get tears flowing for many. Dory asks around the ocean for help finding her parents, to no avail. We fast-forward to the events of the original film, when Dory (now and henceforth voiced, of course, by Ellen DeGeneres) crosses paths with the clownfish Marlin (Albert Brooks) looking for his missing son.

A year after the father and son's reunion, Dory has become like a fun, scatterbrained aunt to Nemo (Hayden Rolence, inevitably replacing Alexander Gould, who provides other voices), sleeping across from their anemone and helping out Mr. Ray (Nemo co-writer Bob Peterson, evidently harboring no ill will after getting replaced as director of The Good Dinosaur) at school. But Dory starts remembering pieces of her childhood and her parents. She decides to look for them in California (cue a brief but welcome current ride with Crush and his fellow sea turtles), but her journey is altered when she is drawn in by the voice of Sigourney Weaver and finds herself undergoing the first stage in the Marine Life Institute's motto "Rescue, Rehabilitate, and Release."

At the Institute, Dory quickly makes a useful friend in Hank (Ed O'Neill), a camouflage-equipped octopus, er, septopus (he's missing a tentacle) who agrees to help Dory look for her parents in exchange for the tag she has on her fin that grants transport to a facility in Cleveland. Hank is but the first and most focal of new characters at the Institute who use their abilities to help Dory. There's also near-sighted whale shark Destiny (Kaitlin Olson) and her neighbor Bailey (Ty Burell), a beluga whale uncertain of his echolocation.

Meanwhile, a distinctly secondary story layer has Marlin and Nemo on the search for their missing friend, encountering such potential allies as sea lions and a mangy bird named Becky who requires an imprint.

Not as far out there as the extensions to the Monsters and Cars universes, Finding Dory is its own thing, more akin to the Toy Story sequels. Like those and the original Nemo, it's a rescue film, but it's done well and never feels like a retread. The only brush with formula is in the climax, which takes the Pixar's "what could go wrong?" principle a few steps too far, demanding all kinds of disbelief suspension as Hank commandeers a truck and drives it at length to try and save the day. The sequence, which may remind you of Toy Story 2's airport finale or the door vault adventure of Monsters, Inc., is a bit belabored and below Pixar's trademark inventiveness. Happily, the rest of the film is not, keeping us invested with colorful characters and witty dialogue.

After his commercially unsuccessful foray into live action on John Carter, Andrew Stanton returns to the director's chair he first occupied on the original film. Stanton shares screenplay credit with Victoria Strouse, a newcomer to Pixar. They both have clear respect for Nemo's universe and though very few characters from the original movie resurface in any meaningful way, the new additions maintain the sensibilities.

Of course, the film looks extraordinary. Pixar's visuals have come a long way in thirteen years, but as on the Toy Story films, the increase in detail and sophistication does not betray the established designs. The film, of course, is in 3D, to no discernible effect. We also get more fine work from the distinctive and always good Thomas Newman, who scored the original film as well as Stanton's WALL•E.

Finding Dory is sure to be a blockbuster, although one wonders if it might have found greater commercial success at a different time. The original film's record numbers were in some part due to a gap in the output of the then guaranteed attraction of computer animation. That isn't to take away anything from the movie, which had universal appeal and all the elements you want in a big, rewatchable summer movie. Toy Story 3 does seem like the model by which to measure Finding Dory and even though movie attendance has dropped in the six summers since, its $400 M+ domestic and $1 billion+ worldwide seem like attainable goals, particularly when Disney's Zootopia and Frozen put up comparable numbers without built-in audiences. Zootopia will pose a threat to Pixar repeating in the Oscars' Best Animated Feature category and there's also Disney's Moana in November which will have voter memory issues on its side.

Though the end credits song, a cover of Nat King Cole's "Unforgettable" by Sia that doesn't really suit the film at all, may drive you to the exits, you absolutely will want to endure the very long scroll of names for a fun tag that brings back the otherwise-absent Tank Gang from the original.

At the other end of the movie is the pre-feature short Piper about an adorable baby sand bird who faces his fear of the waves. It's an appealing directing debut for veteran Pixar animator Alan Barillaro and I suspect likely to earn at least a nomination for the Best Animated Short Oscar.

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