When the opera opens, Paul, a younger middle-class man whose young wife, Marie, has recently died, cannot come to terms with the sad reality of her death. He keeps a "Temple of Memories" in her honor, including paintings, photographs and a lock of her hair. When his friend Frank pays him a visit at his house and urges him to honor Marie by moving on with his life, Paul flies into a rant, and insists that Marie "still lives." He tells Frank that he has met a woman on the streets of Bruges who exactly resembles Marie (indeed, Paul thinks that it is Marie) and invited her back to his home.
Soon, the woman, Marietta, a young and beautiful dancer, appears for her rendezvous with Paul. They talk, she is put off by his odd behavior, but persists in trying to interest him in her charms-she sings and dances seductively, but eventually gets bored and leaves. Paul meanwhile is driven to a state of extreme anxiety.
Torn between his loyalty to Marie and his interest in Marietta he collapses into a chair and begins to hallucinate. He sees Marie's ghost step out of her portrait and urge him not to forget her, but then the vision of Marie changes and tells Paul to go and move on with his life.
After a series of visions in which his pursuit of Marietta alienates him from all his remaining friends, the act ends with Marietta finally overcoming his resistance and leading him offstage locked in a passionate embrace. All this takes place in Paul's imagination.
Paul's vision continues. Back in his house, living with Marietta, he quarrels with her. She gets fed up with his quirks and continuing obsession with Marie and starts to taunt him by dancing seductively while stroking his dead wife's hair. In a rage, Paul grabs the lock of hair and strangles Marietta. Holding her dead body he exclaims "Now she is exactly like Marie." Then he snaps out of his dream. Astonished that Marietta's body is nowhere to be found, he has barely had time to collect his thoughts when his maid informs him that Marietta has come back to pick up her umbrella which she left in the house when she departed a few minutes ago. With the shock of the traumatic dream still fresh in his mind, Paul finally resolves to leave Bruges, let his dead wife rest in peace, and continue his life. In a touching conclusion, with his friend Frank at his side, he vows to start his life anew and slowly leaves behind his house and his "Temple of Memories," for the last time.