Amblimation was the animation production arm of Steven Spielberg's Amblin Entertainment. The studio was shut down in 1997 and some of the Amblimation staff went on to join DreamWorks Animation. It was known for its quieter atmosphere, more subdued acting, and more atmospheric pace compared to a great deal of American animated films; these qualities usually led to underperformance at American box offices and may have factored in the decision to close the studio down. The company's mascot, Fievel Mousekewitz (An American Tail), appears in its production logo. A project to adapt the 1981 Andrew Lloyd Webber musical Cats was in the making, but was abandoned with the studio's closure.
In present-day at New York City, an elderly woman and her granddaughter are walking through Central Park, looking for a memorial statue. As they seat themselves for a rest, the grandmother tells a story about Nome, Alaska, back in 1925 which shifts the film from live-action to animation.
The film opens with a trio of young bluebirds harassing their youngest sibling, Buster (Blaze Berdahl). As Buster leaves his family, he meets an intelligent orange T. rex named Rex (John Goodman) playing golf. He explains to Buster that he was once a ravaging dinosaur, and proceeds to tell the story of how he came to become what he is today.
Several years after settling in to their new home in The Bronx, New York, the impoverished Mousekewitz family soon finds that conditions are not as ideal as they had hoped, as they find themselves still struggling against the attacks of mouse-hungry felines. Fievel spends his days thinking about the wild west dog-sheriff Wylie Burp, while his sister, Tanya, dreams of becoming a singer. Meanwhile, Tiger's girlfriend Miss Kitty leaves him to find a new life out West, remarking that perhaps she's looking for "a cat that's more like a dog."