Place: A barge on the Seine in Paris.
Time: 1910.

It is close to sundown in Paris, and the stevedores work unloading Michele's barge. Giorgetta, Michele's wife, asks her husband if she can bring wine to the workers. He agrees but does not join them because she refuses his kiss. The stevedores start dancing to the music of a nearby organ grinder and one of them steps on Giorgetta's foot. Luigi, a stevedore, dances with her, and it is evident that there is something between them. Upon hearing of Michele's return the stevedores' gathering breaks up.

Work is getting scarce and Giorgetta and Michele discuss which of the stevedores should be dismissed; she prefers that it be anyone other than Luigi despite him being Michele's first choice. Soon the conversation turns into a fight. La Frugola enters, looking for Talpa, her husband and one of the stevedores. She shows everyone the fruits of her scavenging in Paris and scolds the men for their drinking. Luigi laments his lot in life, and La Frugola sings of her wish to one day buy a house in the country where she and her husband can retire. Giorgetta and Luigi sing a duet about the town where they were both born.

The stevedores depart except for Luigi, who asks Michele to dismiss him and let him off in Rouen, but Michele convinces him against this, saying there is not enough work in Rouen. When they are alone, Giorgetta asks Luigi why he requested to be dismissed; the pair acknowledge their love. They plan to meet later that evening upon the signal of a match being lit on board. By now Luigi seems determined to kill Michele and flee with Giorgetta.

Michele later reminisces with Giorgetta of the days before their child died and how he could cover the two of them under his cloak. He is distressed about being twice her age; she comforts him but she still will not kiss him, and goes off.

Michele wonders aloud if Giorgetta is still faithful to him and ponders who might have changed her so much. He reviews the list of men who have shared in their lives but dismisses each of them as improbable. Michele lights his pipe and Luigi, seeing it from afar, thinks that it is Giorgetta's signal. He returns to the barge and is confronted by Michele. In the ensuing fight, Michele gets the upper hand and forces Luigi to confess his affair before killing him and hiding the body under his cloak. Giorgetta returns to the barge, feigning remorse, and Michele opens wide the cloak to reveal her dead lover.

Place: A huge, dark hall in a castle, with seven locked doors.
Time: Not defined.

Judith and Bluebeard arrive at his castle, which is all dark. Bluebeard asks Judith if she wants to stay and even offers her an opportunity to leave, but she decides to stay. Judith insists that all the doors be opened, to allow light to enter into the forbidding interior, insisting further that her demands are based on her love for Bluebeard. Bluebeard refuses, saying that there are private places not to be explored by others, and asking Judith to love him but ask no questions. Judith persists, and eventually prevails over his resistance.

The first door opens to reveal a torture chamber, stained with blood. Repelled, but then intrigued, Judith pushes on. Behind the second door is a storehouse of weapons, and behind the third a storehouse of riches. Bluebeard urges her on. Behind the fourth door is a secret garden of great beauty; behind the fifth, a window onto Bluebeard's vast kingdom. All is now sunlit, but blood has stained the riches, watered the garden, and grim clouds throw blood-red shadows over Bluebeard's kingdom.

Bluebeard pleads with her to stop: the castle is as bright as it can get, and will not get any brighter, but Judith refuses to be stopped after coming this far, and opens the penultimate sixth door, as a shadow passes over the castle. This is the first room that has not been somehow stained with blood; a silent silvery lake is all that lies within, "a lake of tears". Bluebeard begs Judith to simply love him, and ask no more questions. The last door must be shut forever. But she persists, asking him about his former wives, and then accusing him of having murdered them, suggesting that their blood was the blood everywhere, that their tears were those that filled the lake, and that their bodies lie behind the last door. At this, Bluebeard hands over the last key.

Behind the door are Bluebeard's three former wives, but still alive, dressed in crowns and jewellery. They emerge silently, and Bluebeard, overcome with emotion, prostrates himself before them and praises each in turn (as his wives of dawn, midday and dusk), finally turning to Judith and beginning to praise her as his fourth wife (of the night). She is horrified and begs him to stop, but it is too late. He dresses her in the jewellery they wear, which she finds exceedingly heavy. Her head drooping under the weight, she follows the other wives along a beam of moonlight through the seventh door. It closes behind her, and Bluebeard is left alone as all fades to total darkness.