Swan Lake is generally presented in either four acts, four scenes (primarily outside Russia and Eastern Europe) or three acts, four scenes (primarily in Russia and Eastern Europe). The biggest difference of productions all over the world is that the ending, originally tragic, is now sometimes altered to a happy ending.

Prologue
Some productions include a prologue that shows how Odette first meets Rothbart, who turns Odette into a swan.

Act 1

A magnificent park before a palace

[Scène: Allegro giusto] Prince Siegfried is celebrating his birthday with his tutor, friends and peasants [Waltz]. The revelries are interrupted by Siegfried's mother, the Queen [Scène: Allegro moderato], who is concerned about her son's carefree lifestyle. She tells him that he must choose a bride at the royal ball the following evening (some productions include the presentation of some possible candidates). Siegfried is upset that he cannot marry for love. His friend Benno and the tutor try to lift his troubled mood. As evening falls [Sujet], Benno sees a flock of swans flying overhead and suggests they go on a hunt [Finale I]. Siegfried and his friends take their crossbows and set off in pursuit of the swans.

Act 2

A lakeside clearing in a forest by the ruins of a chapel. A moonlit night.

The "Valse des cygnes" from act 2 of the Ivanov/Petipa edition of Swan Lake
Siegfried has become separated from his friends. He arrives at the lakeside clearing, just as a flock of swans land [Scène. Moderato]. He aims his crossbow [Scène. Allegro moderato], but freezes when one of them transforms into a beautiful maiden, Odette [Scène. Moderato]. At first, she is terrified of Siegfried. When he promises not to harm her, she explains she and her companions are victims of a spell cast by the evil owl-like sorcerer Rothbart. By day they are turned into swans and only at night, by the side of the enchanted lake – created from the tears of Odette's mother – do they return to human form. The spell can only be broken if one who has never loved before swears to love Odette forever. Rothbart suddenly appears [Scène. Allegro vivo]. Siegfried threatens to kill him but Odette intercedes – if Rothbart dies before the spell is broken, it can never be undone.

As Rothbart disappears, the swan maidens fill the clearing [Scène: Allegro, Moderato assai quasi andante]. Siegfried breaks his crossbow, and sets about winning Odette's trust as the two fall in love. But as dawn arrives, the evil spell draws Odette and her companions back to the lake and they are turned into swans again.

Act 3

An opulent hall in the palace

Guests arrive at the palace for a costume ball. Six princesses are presented to the prince [Entrance of the Guests and Waltz], as candidates for marriage. Rothbart arrives in disguise [Scène: Allegro, Allegro giusto] with his daughter, Odile, who is transformed to look like Odette. Though the princesses try to attract the prince with their dances [Pas de six], Siegfried has eyes only for Odile. [Scène: Allegro, Tempo di valse, Allegro vivo] Odette appears (usually at the castle window) and attempts to warn Siegfried, but he does not see her. He then proclaims to the court that he will marry "Odette" (Odile) before Rothbart shows him a magical vision of Odette. Grief-stricken and realizing his mistake, Siegfried hurries back to the lake.

Act 4

By the lakeside

Odette is distraught. The swan-maidens try to comfort her. Siegfried returns to the lake and makes a passionate apology. She forgives him, but his betrayal cannot be undone. Rather than remain a swan forever, Odette chooses to die. Siegfried chooses to die with her and they leap into the lake. This breaks Rothbart's spell over the swan maidens, causing him to lose his power over them and he dies. In an apotheosis, the swan maidens watch as Siegfried and Odette ascend into the Heavens together, forever united in love.

Lise and Colas are in love and want to marry. However, the Widow Simone wants Lise to marry the dimwitted, but extremely rich, Alain, and has arranged (with Alain's father Thomas) for a marriage contract between Lise and Alain. The Widow Simone does her best to keep Lise and Colas apart, but is unsuccessful in her attempts to do so.

At harvest time the Widow Simone and Lise are taken to the field for a picnic lunch by Thomas and Alain. The farm workers join in a ribbon dance around a maypole, and the girls also join in a clog dance with the Widow Simone. There is a thunderstorm and everyone rushes for shelter. Alain is carried away on the wind by his open umbrella.

The Widow Simone and Lise return to their home. The widow wants Lise to sit down at the spinning wheel and spin, but Lise spins while she is up dancing, nearly strangling the widow. After a while, the widow wants Lise to dance, and Lise shows signs of unhappiness, but obliges. The widow takes a tambourine to play in time with Lise's dancing. When the widow is asleep, Lise tries to steal the key from the widow's pocket, to prevent the widow from locking her in, but is unsuccessful. The crops are brought in by the farm workers, and the widow then leaves the house (after locking the door behind her to prevent Lise from leaving the house). Lise thinks about Colas and mimes being the mother of a large number of children. To her embarrassment, Colas suddenly rises from the stacked crops. At the sound of the Widow Simone's returning to the house, Lise and Colas look around desperately for a place where he can hide. Not finding anywhere suitable in the living room, Lise takes Colas to her room, and she returns to the living room just before Widow Simone enters the house. The Widow Simone orders Lise to go to her room and put on her wedding dress for her forthcoming marriage to Alain. The horrified Lise tries to remain where she is, but the Widow Simone pushes Lise into her room and locks the door.

Thomas arrives with his son Alain (who is still clutching his umbrella). They are accompanied by a notary who is to act as witness to the marriage. The farm workers (friends of both Lise and Colas) also arrive. The Widow Simone gives Alain the key to Lise's room. When Alain unlocks the door to Lise's room, Lise appears in her wedding dress, accompanied by Colas. Thomas and Alain take offence, and the enraged Thomas tears up the marriage contract. Thomas, Alain and the notary leave the house in dudgeon. Lise and Colas then beg the Widow Simone to look favourably upon their suit. Love conquers all and the widow relents. Joyfully celebrating the happy outcome for Lise and Colas, everyone leaves, and the house is left quiet and empty, until Alain returns for his umbrella which he had accidentally left behind. So Alain is also happy with the love of his life – his umbrella.

Don Quixote's Study

Bachelor Sanson Carrasco is seen covering a bookcase with wallpaper, while Antonina is putting some rusty old armour and a helmet made of pasteboard into a cupboard. Don Quixote de la Mancha enters, reading a book. He goes to the bookcase and, not finding it, believes it has been stolen by evil magicians. Then he settles into an armchair and continues reading. He delights in stories of brave knights, fabulous giants and other fantastical creatures, but most of all Don Quixote dreams of his beloved Dulcinea, a woman that he believes to be so lovely and noble that she must be divinity. Gradually he nods and falls asleep to dream of their romantic adventures. Darkness falls.

Suddenly his servant, Sancho Panza, climbs hurriedly through the window. In pursuit are several angry women from the market from whom he has stolen bread and a chicken. Awakened by the commotion, Don Quixote sends the women away. Don Quixote tells Sancho that he is determined to seek adventures as a knight-errant, all the while searching for his beloved Dulcinea. He shows him the pasteboard helmet, which, with one sweep from his sword, becomes a shapeless mass on the floor. Antonina suggests that he should use a shaving basin instead, which would make a splendid helmet. Don Quixote enthusiastically agrees and, placing it on his head, orders Sancho to bring him his armour, sword and spear, and to make ready his horse, Rocinante.

Act I

A market-place in Barcelona

Kitri, an inn-keeper's daughter, steals out of her house to meet her beloved, the barber Basilio. Her father, Lorenzo, sees the lovers and sends Basilio away, bringing Kitri to tears. Now comes the rich nobleman Gamache, who, likewise in love with Kitri, goes to Lorenzo and asks for his daughter's hand. The innkeeper accepts with delight but Kitri, appalled at the thought of wedding the foppish nobleman, runs away.

Dancing begins in the square and some toreadors try to kidnap the girls they fancy, but their relatives and lovers hasten to their aid. At this moment Don Quixote arrives mounted on Rocinante, followed by Sancho, who is riding a donkey. At his master's command Sancho sounds his rusted horn, causing the townspeople to cover their ears. Lorenzo runs out of his inn, and Don Quixote, taking him for the lord of a famous castle, dismounts Rocinante and, falling to his knees, begs to be allowed to serve him. Charmed, Lorenzo invites the knight to sit on his balcony. Sancho remains in the square where he is surrounded by girls who induce him to take part in a game of blind man's bluff. Then some boys bring in a blanket on which they place Sancho and proceed to toss him into the air. Don Quixote hurries to his assistance and sets him free.

Peasants gather in the square and dancing resumes. Kitri returns and, noticing her, Don Quixote acclaims her as his Dulcinea, whom evil magicians have reduced to human form. Becoming jealous of her affection for Basilio, Don Quixote attempts to woo her by partnering her in a minuet. Lorenzo berates Kitri for carrying on with Basilio. Kitri and Basilio then run away, and Lorenzo and Gamache follow them. Don Quixote orders Sancho to bring Rocinante, so that he may also set out in pursuit.

Act II

Scene 1 – A camp of gypsies among the windmills outside the village

Kitri, disguised as a boy is seen walking with Harlequin from a troupe of travelling actors. They guess she is a girl and ask her to stay with them.

Scene 2 - The Puppet Theatre

A clown is seen walking with Graziosa, the gypsy chief's daughter. A gypsy tells the chief of the approach of Don Quixote. The chief plans a trick for his benefit and, putting on a mantle crown, sits down as though he were a king on a throne. Don Quixote is deceived and kneels to the chief in homage. The chief bids that he sit beside him and orders a festival to be given in his honor. This begins with Gypsy dances and is followed by a performance of the marionette theatre. Don Quixote is delighted with the entertainment but, mistaking the heroine for his Dulcinea and the marionettes for soldiers attacking her, he rises to assault them. The gypsies are terrified. At this moment the clown and Graziosa run away.

Scene 3 - The Windmills

Flushed with victory, the knight kneels and renders thanks to heaven. Seeing the moon, he takes it for his Dulcinea and tries to get to her. As he approaches the windmills he can see the moon no longer and thinks that evil magicians have hidden his beloved mistress. So, spear in hand, he tilts at the wings of the windmill, which he mistakes for a giant. Alas, the knight is caught by one of the wings and flung into the air. He falls unconscious at Sancho's feet.

Scene 4 – A forest

Through the trees appears Sancho leading Rocinante, upon which sits the wounded Don Quixote. The servant lifts his master down and places him on the grass, so that he may rest. Then, tying up the horse, he goes to sleep. Don Quixote also tries to sleep, but is troubled by fantastic dreams.

Scene 5 – The enchanted Garden of Dulcinea

Fairies appear surrounded by gnomes and Don Quixote finds himself dressed in shining armor. Then comes a succession of fearsome monsters, the last being a gigantic spider, who spins a web. The knight attacks the spider, which he slashes in half with his sword. At that same moment the spider's web vanishes to reveal a beautiful garden, filled with dryads and beautiful women, presided over by the Queen of the Dryads and Amor. Among them is Dulcinea and Don Quixote kneels before his beloved. At this moment everything vanishes.

Act III

The Square

Back at the square, Kitri and Basilio join those who are dancing. At the height of the merriment, Lorenzo and Gamache arrive, followed by Don Quixote and Sancho. Seeing his daughter, Lorenzo decides to give his blessing to her union with the nobleman Gamache. Basilio becomes annoyed and, reproaching Kitri for her unfaithfulness, draws a sword and stabs himself. As he lies dying he begs Lorenzo to unite him with Kitri, but Lorenzo and Gamache refuse. Don Quixote approaches Gamache and challenges him to a duel for having refused a dying man's wish. Gamache declines to fight and the merrymakers drive him out of the inn. Taking pity, Lorenzo agrees to unite Basilio and Kitri. At this moment, Basilio pulls out the sword and tells everyone it was a joke.

Act IV

The Tavern

A magnificent feast is held in honour of Don Quixote. Suddenly the Knight of the Silver Moon challenges him to a duel, which results in the latter being vanquished. The victorious knight proves to be none other than Bachelor Sanson Carrasco, who forces Don Quixote to vow that he will not unsheathe his sword for a whole year. The sorrowful knight, true to his vow, takes up his warlike gear and, followed by Sancho, sets out for home.