A Polish man dies leaving behind two sons that he ignored. Middle-aged Jerzy (Jerzy Stuhr) locates his brother Artur (Zbigniew Zamachowski), a singer in a rock group called "City Death." They have not seen each other for two years and were never very close. At their father's flat they are surprised to find a very valuable stamp collection barricaded behind a steel door, various locks, and file cabinets. A man shows up with the news that their father owes him money and offers to take the equivalent from the stamp collection. They decline that offer and promise to repay him.

Once Jerzy and Artur find out that their father's stamps are worth a fortune, they are overcome with fantasies about even more wealth. Although they could use the money right away, they decide to hang on to the collection. On this path, the two brothers slowly become enslaved to fear, anxiety, and distrust of others. A shady stamp dealer tells them that he has the rare third stamp they need to complete a unique series but he won't take money for it — if he really wants it, Jerzy will have to donate one of his kidneys to save the man's daughter's life.

In this black comedy, Krzysztof Kieslowski presents a wry interpretation of "Thou shalt not covet thy neighbor's goods." The Sufi writer James Frager has observed: "Avoid greed, for greed in itself is poverty." Jerzy and Artur's lives are impoverished once they get caught up in schemes to make more money off their father's stamp collection. They find themselves out of their element contending with individuals more malevolent and clever than they are. Jerzy and Artur even turn against each other. But that is not the end.

Kieslowski, a compassionate director, chooses to conclude this dramatic and unique series on the Ten Commandments not with a bang but with the redeeming sound of laughter. The final message of The Decalogue is that no matter what our flaws or our failures, no matter how many commandments we have violated, we are given the strength and the courage to pick ourselves up off the floor and begin again.