A polar bear of many words, Norm's greatest gripe is simple: there is no room for tourists in the Arctic. But when a maniacal developer threatens to build luxury condos in his own backyard, Norm does what all normal polar bears would do: he heads to New York City to stop it. With a cast of ragtag lemmings at his side, Norm takes on the Big Apple, big business, and a big identity crisis to save the day.

Roddy is a decidedly upper-crust "society mouse" who lives the life of a pampered pet in a posh Kensington flat. When a sewer rat named Sid comes out of the sink, he desides he had hit the jackpot. Roddy schemes to rid himself of Sid by luring him into the "whirlpool." Sid may be an ignorant slob, but he's no fool, but it is Roddy who winds up being flushed away into the bustling sewer world of Ratropolis. There Roddy meets Rita, an enterprising scavenger...