There are a number of ways for an animated film about rats in a sewer to go wrong. Most obviously, the premise is just kind of disgusting. But when my companion turned to me halfway through the movie and matter-of-factly commented that the Hugh Jackman-voiced rat “looked handsome in that shirt,” it was evident the filmmakers had effectively gotten beyond the ‘ick’ factor.

Made by Aardman Animations, “Flushed Away” retains the look and feel of the company’s famous “claymation” productions — “Wallace & Gromit” and “Chicken Run” — although it is Aardman’s first CGI project. And, because the animation makes the characters look more human than rodent, it is fairly easy to get beyond the film’s gross concept.

“Flushed” follows Roddy (voiced by Hugh Jackman), a pet rat living in a lush London penthouse who is flushed down the toilet and encounters a rat metropolis in the sewers. The inexperienced Roddy meets the bold and eccentric Rita (Kate Winslet), and an adventure ensues as the pair run into trouble with The Toad (Ian McKellen) and his French cousin, Le Frog (Jean Reno). And, though he was once only concerned with his toys, after assimilating into the sewer culture Roddy falls in love with Rita and begins to see the value of family and to re-evaluate his priorities in life.

If the plot sounds like every other animated movie you have ever seen, that may be because it is. The movie is funny, but it has neither the originality of “Shrek” nor the unadulterated fun of “Finding Nemo.”

As the film progressed, it became increasingly obvious that the CGI-animation genre is running thin. The past few years have offered cleverly-named movies covering just about every member of the animal kingdom. It’s hard to differentiate between “Madagascar,” “Over the Hedge” and “Open Season” because they are almost the same movie. Possible plots have become so sparse that we are left with movies about rats in a sewer (in fact, Pixar’s forthcoming “Ratatuille” will again cover the apparently fascinating rich-poor divide in rat communities).

In the first five minutes of “Flushed,” the animators acknowledged this redundancy with quick references to “Wallace & Gromit” and “Chicken Run,” as well as an amusing jab at “Finding Nemo.” Throughout the movie, the plot cleverly plays on animated-film conventions and, in many instances, effectively turns them on their head. For example, the film includes the standard “group of funny animals who do funny things as a group,” following in the footsteps of the dodos in “Ice Age” or penguins in “Madagascar.” But, rather than being cute and cuddly, “Flushed Away” features a clan of slimy, singing slugs.

But ultimately, the film’s acknowledgment of its difficult situation only served to accentuate how derivative the plot is. 2002’s “Lilo & Stitch” summarized the film’s central idea better than “Flushed Away” could — “‘Ohana’ means family, which means no one gets left behind.”

“Flushed” will probably entertain you, but it is unlikely that you will remember it more than a week after leaving the theater. One of the film’s finer touches is the character of Rita’s amnesic grandmother (Rachel Rawlinson). Ironically, she’s about the only thing you’ll stand to remember.