During an appointment with her doctor, thirty-year-old Charlotte discovers that she's pregnant. This is not the ideal moment to have a child: she's looking for a job and sharing an apartment with her friend Clémentine.
Through Julie Borgne, who works for an association providing home help, Charlotte encounters eighty-four-year-old Madeleine, who is very alert and lives alone in a large apartment whose huge terrace provides a view over the rooftops of Paris - of which Julie is very envious.
During the meeting, Julie boasts about Charlotte's talents while making the most of the rum-based drinks Madeleine has offered them. In an advanced state of drunkeness, she leaves and lets the other two women get to know each other better. Madeleine can tell that Charlotte has never done this kind of work before, and Charlotte confirms that it was the employment office that sent her to the association. Madeleine decides to think things over before giving her response, but when Charlottre returns a few moments later with a small bunch of flowers, the elderly woman proposes that she start work the following Monday.
When Charlotte arrives to start her job, she notices that someone else is in her place. Madeleine is horrible to this lady's companion, who quits immediately.
Madeleine then employs Charlotte for a 3-month trial period. She outlines her expectations and demands. The old woman isn't always easy and hides some deep-seated grief that she calms by talking to a photo, hanging on the wall of one of the rooms, of a woman named Louise. Charlotte catches her doing it one day, provoking Madeleine to anger.
Following Julie's instructions, Charlotte is always vigilant to ensure that Madeleine takes all her medication - in the right doses.
One day, on the pretext of looking for a sewing machine, Madeleine takes her to visit an empty apartment that she owns, and which is on the floor just below hers. Clémentine tells Charlotte that her fiancé is going to come to live with them in their shared apartment. Charlotte decides to squat in Madeleine's empty apartment and, to keep her precarious job, she hides her pregnancy by flattening her stomach with bandages..
Unbeknownst to Charlotte, Madeleine quickly discovers that the young woman has moved in downstairs, but, against all expectations, this indirect shared apartment living brings them closer, although neither lets the other know their secrets.
When a couple of friends pay her a visit, Madeleine demonstrates the kind of death she would like to have. The couple is dismayed, whereas Charlotte thinks it's a sign.
The two women spend a lot of time together speaking about this and that. A political activist all her life, Madeleine has a great passion for Louise Michel and dreams of being buried beside the renowned activist. Charlotte and Madeleine go to the cemetery where Louise Michel is buried to convince its manager that Madeleine's wishes are reasonable. He accepts. Charlotte is delighted.
Madeleine is a lot less so; she feels threatened, without knowing where the threats are coming from.
Is it the presence of Louise in her mind? Louise has been making increasingly frequent "appearances." Madeleine can feel her hanging around, even though Madeleine hasn't seen her in years. When Charlotte doesn't come to work one day, Madeleine goes downstairs to see her and discovers that she's had a miscarriage. Madeleine takes care of the young woman as best she's able and calls a doctor.
Madeleine and Charlotte tacitly agree to part ways. Charlotte says goodbye and goes downstairs to pack her bags. The sound of an argument breaks out below. Madeleine, intrigued, listens and then goes downstairs. The door to Charlotte's apartment is open. Madeleine realizes that her daughter Louise, who disappeared years ago and who hates her, has used her own daughter Charlotte to try to hasten Madeleine's end, so that Louise could inherit more quickly. But Charlotte no longer wants to go through with the plan.
