The closing notes of the celebrated mazurka in the ouverture of the ballet linger in the air, as the village square fills with peasants going out to work in the fields. It is corn harvest time. Spotlighted on the balcony of the house of Doctor Coppelius, an eccentric, mysterious and slightly sinister character who also makes toys, stands a young girl, motionless and imperturbable. Swanhilda notices the unknown girl on the balcony and attempts to catch her attention, but fails to do so and goes off.

Swanhilda’s fiancé, Franz, arrives. He too is impressed by the beauty of the girl on the balcony and tries to court her. Returning with a group of girl friends, Swanhilda catches him in the act of blowing the unknown girl a kiss and in a fit of jealousy hurries away, leaving him alone. With the peasants who have come back from the fields with their shocks of corn, Franz dances the mazurka.

On her return to the square, Swanhilda tells him she is no longer in love with him and does not wish to marry him. Moreover, at the end of the pas de deux the girl hears no rattle from the ear of corn, a sign of love according to superstition, and this strengthens her resolve. In his attempt to recapture her, Franz spurs the villagers to dance a csardas. Swanhilda not only joins in but forgives him too. The girl’s father invites everybody to go home, for tomorrow will be a big holiday to celebrate the marriage of the betrothed.

In the now empty square Coppelius comes out for a short walk. On his way to the inn, he puts the key of his house in his pocket. But he is waylaid by tipsy youths, who provoke him, knock him down and throw him into a fountain, where he loses his key which Swanhilda finds. With her friends, she creeps furtively into the old toy-maker’s house, with the intention of confronting her rival face to face. Coming back from the inn, Coppelius not only cannot find the key to his house, but also notices that the front door is wide open. He rushes in, while Franz, unaware of what has been going on, climbs into the building by means of a ladder.