The background artwork is stunning, almost photorealistic, and there was an amusing bit at the beginning, where the credits ran as street signs, billboards, and ads on the sides of buses and trucks. By the way, the artwork really captured what Tokyo looks like and much of the way they act. I loved the gossip session among the neighbors around the ruins of Sachiko's former house. That's exactly the way older women in Tokyo neighborhoods gossip.
In the story, three homeless people, including an alcoholic, a drag queen, and a runaway teenage girl, find a baby girl in a trash heap on Christmas Eve. The alcoholic wants to turn her in to the police right away, but the drag queen "always wanted to be mother" and insists that the child is a gift from heaven. Eventually, the three homeless people start wandering around the city in search of the baby's mother. After many plot twists, they end up in a stop frame where everyone's problems can potentially be solved.
A remarkable feature of this film is the characterization of the homeless people. Each of them is likable but seriously flawed, and the portrayals are largely sympathetic. The script is also sympathetic to illegal Brazilian immigrants, and even a yakuza gangster does a good deed.
I'd place this right up there with Grave of the Fireflies and Spirited Away as one of my all-time favorite anime.
These stills give you some idea of the quality of the animation.