Papa tells Fievel and his family inspiring ideas about America. He mentions that it has no cats and that everyone is happy living there. His story is interrupted when a group of cats attack the family's neighborhood.
Mice from all over group up and create a plan to drive away the cats, who threaten their livelihood. They created the Giant Mouse of Minsk, which they call their "Secret Weapon," and used it to scare away all of the cats in the city.
As Fievel gives up hope of ever finding his family, Henri sings a song to lift his spirits and make him optimistic. Henri also suggests to Fievel that America is the place to find hope and opportunity.
When the other mice warn of a cat, Fievel doesn't believe them. His father once told him that cats don't exist in America, and he shares that belief. He changes his mind and runs for his life when a black cat attacks him in an attempt to eat him.