An American Tail 3 The Treasure Of Manhattan Island (1998)

Plot
The story begins in setting sometime after the first movie (which began in 1885) presumably between 1886 and 1889, as Fievel and Tony discover that an ancient treasure lies underneath  when snooping around an abandoned subway (the system) and stumbling upon the remains of a dead mouse clutching a treasure map, deciding they must find it with the help of an  Tony knows: Dr. Dithering, along with fighting five villains as well.

The movie focuses on the relationship between the over-exploited workers of a (in this case, a  production line) and the factory's  owners: Mr. Grasping, Mr. Toplofty  and Mr. O'Bloat. It also focuses on the plight of the Native Americans in the United States. The treasure under Manhattan turns out to be a group of mice living a long distance beneath the surface (far below the sewers, riding in ) that decided to hide when they saw how the first Europeans only brought war and disease with them and didn't want to wait for the European mice to do the same to them. An emotional scene ensues when Fievel must struggle with how cruel his own people, the Europeans, were (and still are at the time the film takes place) to the natives of America.

The sachem, Chief Wulisso, decides to send his daughter Cholena (Elaine Bilstad), to the surface to see if they have "changed their ways." Upon their return, Scuttlebutt (one of the members of the expedition to find the treasure) reports to the villains unbeknownst to the rest of the members of the expedition, who then decide to use this to their advantage. They lie to all the workers of the sweatshop about Cholena (obviously not by name), telling them that she is their enemy. The mouse Chief, McBrusque  and Scuttlebutt engage in a bout of, scavenging every nook and cranny until they find her. After the angry mouse mob try to capture Cholena and anyone else involved with her, Fievel and his friends decide to take Cholena back underground, but the police find out and go after them. Meanwhile, everyone finds out about Dr. Dithering's friendship with the Indian and take him to the butcher shop for his execution. Papa tells everyone about how madness like this is why they all left for America and should work together to become friends with those different from them as the fellow Americans they are. Tiger saves Dr. Dithering from the villains, who escape and order McBrusque and his men to find and murder the Native Americans. Upon returning Cholena to her home, they tell the chief what is happening. McBrusque, Scuttlebutt, and the other police officers show up to the village, but the Chief, the Native Americans, Fievel and his friends drive the villains away. The chief gives them a  to collapse the tunnel connecting the Native Americans to the outside world. But before they can do so, they are ambushed by the enraged McBrusque and Scuttlebutt who attempt to kill the kids once and for all, but the two crooks are overpowered and Fievel manages to set of the bomb. This floods the tunnel, together with McBrusque and Scuttlebutt as they fall into the to their deaths. Tony and Tanya managed to reach higher ground, but Fievel is seemingly carried off by the current. When the water recedes Tanya and Tony desperately search through the mud to find him, before giving up. But just then, Fievel breaks through the surface, and they all three share a muddy group hug, thankful that everyone survived.

The movie ends with Fievel's papa forming a and the villains agreeing amongst themselves to negotiate "with that riff-raff" because otherwise, they'll go on strike and make them go bankrupt while Tiger the cat, who is now the new police chief, watches them. The last scene is Fievel seeing, through a foldable telescope, Cholena and her father disappearing into a hidden door at the foot of a statue, which pleases Fievel.