Things Change is set in Chicago where Gino (Don Ameche), an elderly Italian immigrant works in a shoeshine shop. Mr. Green, the local Mafia head, wants him to confess to a crime that he committed. In exchange for a three year prison term, Gino will get a fishing boat in Sicily. Jerry (Joe Mantegna), is a low-level member of the crime clan who must coach Gino on the phony confession and deliver him to the police. Convinced that the old man could use one last fling, he takes him to Lake Tahoe for the weekend. There Gino is mistaken for a Mafia kingpin and given the hotel's suite, unlimited credit, a limo and girls. When the local Mafia don (Robert Prosky) invites him to his estate, Jerry gasps in horror of what will happen when the truth is discovered about their real identity.

Writer and director David Mamet, who dealt with deceit in House of Games, focuses with laser-like intensity on the ethical importance of keeping one's word. Gino refuses to go back on his promise to Mr. Green. He is like Thomas More in the film A Man for All Seasons who explains why he cannot break an oath: "when a man makes a promise, he puts himself in his own hands like water. And if he opens his fingers to let it out, he need not hope to find himself again." This exceptional film is about the rock solid value of keeping commitments in a world where everything else is fluid and fleeting.