Mr. Pocket opens a new hotel, the Pocket Plaza, aka the Plaza Hotel in New York City. There is a new English friend, Pia Pocket, an identical cousin of Polly, who dreams of being a great rock star. Polly's father is arrested at an airport in Indonesia and Polly now has to present the hotel opening.
Ten years before the first film, there was a period of enormous political turmoil. Fearless agents were recruited for espionage missions against enemy spies. Gregorio Cortez and Ingrid Avellan (Antonio Banderas and Carla Gugino) were enemy spies assigned to kill each other, but instead they fell in love and married. After an atypical wedding, Gregorio and Ingrid took a break from espionage and started a family.
Set in the fictional town of Junctionville, NY around the turn of the 20th century, Santa Claus is offended by an anonymous letter printed in the town's newspaper (and signed "all of us") claiming that he doesn't exist. In response, Santa returns the entire town's letters to them unopened. Upon reading the anonymous letter printed in the newspaper, Father Mouse (voiced by George Gobel) — a mouse assistant to the human clockmaker Joshua Trundle (voiced by Joel Grey, the credited narrator) — immediately suspects that his brainy son Albert is its author. Albert (voiced by Tammy Grimes) confirms his suspicions, repeating the letter verbatim to him.
The film is presented in a nonlinear narrative, as it jumps from various days within the 500-day span of Tom and Summer's relationship, indicated by an animation that includes the day's number; the following summary is a linear version of the events of the film.
While playing baseball on a busy street in Greenpoint, Mickey is struck by a car. Though he fully recovers from his injuries, Mickey meets several other kids in the hospital who weren't so lucky. Instantly developing a sense of civic responsibility, the Gang members establish the "1-2-3 Go Safety Society," dedicated to lowering the number of auto injuries in their community.
In April 1945, outside the titular address in the fictional town of Gibbsville, Pennsylvania, a radio reporter is describing the funeral of distinguished attorney Joseph Chapin (Gary Cooper). While his shrewish wife Edith (Geraldine Fitzgerald) delivers his eulogy, daughter Ann (Diane Varsi) thinks back to Joe's fiftieth birthday celebration five years earlier.