Time: Within the period July to December, in an undefined year in the 1780s.
Place: Wetzlar in Germany.

Act 1

In July, the widowed Bailiff (a Magistrate, rather than one who comes to seize property), is teaching his six youngest children a Christmas carol ("Noël! Jésus vient de naître"). His drinking companions, Johann and Schmidt, arrive as Charlotte, the eldest daughter, dresses for a ball. Since her fiancé Albert is away, she is to be escorted by Werther, whom the Bailiff and his companions find gloomy. Werther arrives ("O Nature, pleine de grâce"), and watches as Charlotte prepares her young siblings' supper, just as her mother had before she died. He greets her and they leave for the ball. Albert returns unexpectedly after a six-month trip. He is unsure of Charlotte's intentions and disappointed not to find her at home, but is reassured and consoled by Charlotte's younger sister Sophie. He leaves after promising to return in the morning. After an orchestral interlude, Werther and Charlotte return very late; he is already enamoured of her. His declaration of love is interrupted by the announcement of Albert's return. Charlotte recalls how she promised her dying mother she would marry Albert. Werther is in despair.

Act 2

It is three months later, and Charlotte and Albert are now married. They walk happily to church to celebrate the minister's 50th wedding anniversary, followed by the disconsolate Werther ("Un autre est son époux!"). First Albert and then Sophie ("Du gai soleil, plein de flamme") try to cheer him up. When Charlotte exits the church, he speaks to her of their first meeting. Charlotte begs Werther to leave her, though she indicates that she would be willing to receive him again on Christmas Day. Werther contemplates suicide ("Lorsque l'enfant revient d'un voyage"). He encounters Sophie but the tearful girl does not understand his distressing behavior. Albert now realizes that Werther loves Charlotte.

Act 3

Charlotte is at home alone on Christmas Eve. She spends time rereading the letters that she has received from Werther ("Werther! Qui m'aurait dit ... Ces lettres!"), wondering how the young poet is and how she had the strength to send him away. Sophie comes in and tries to cheer up her older sister ("Ah! le rire est béni"), though Charlotte is not to be consoled ("Va! laisse couler mes larmes"). Suddenly Werther appears, and while he reads to her some poetry of Ossian ("Pourquoi me réveiller?"), he realizes that she does indeed return his love. They embrace for a moment, but she quickly bids him farewell. He leaves with thoughts of suicide. Albert returns home to find his wife distraught. Werther sends a messenger to Albert, requesting to borrow his pistols, explaining he is going on an extended trip. After the servant has taken them, Charlotte has a terrible premonition and hurries to find Werther. An orchestral intermezzo ("La nuit de Noël") leads without a break into the final Act.

Act 4

"The death of Werther": At Werther's apartment, Charlotte has arrived too late to stop him from shooting himself; he is dying. She consoles him by declaring her love. He asks for forgiveness. After he dies, Charlotte faints. Outside children are heard singing the Christmas carol.