In this new series, Le Jour où tout a basculé (The Day When Everything Turned Upside Down), a mother and son's close relationship is about to change. Enzo, who lives with his mother Murielle, runs into a man with a distinctive tattoo. Determined to track down the man, whom he believes to be his father, he starts an inquiry of his own despite his mother's skepticism.

In this episode of "Le Jour où tout a basculé" (The Day Everything Turned Upside Down), Sybille, a bored and lonely housewife, has developed the peculiar habit of spying on her neighbors across the street, much to her husband's dismay.

Sybille's anxiety escalates as the spying continues. The stranger across the street is staring out the window all day long. To make matters worse, her husband comes home late, very late, and is less than sympathetic to her plight...

Sybille and Édouard are still at odds with each other as Sybille now accuses him point-blank of having an affair with Vanessa. The mysterious neighbor doesn't cooperate with Édouard's scheming but pursues her own agenda.

Sybille and Édouard meet for drinks at Vanessa's apartment. Vanessa finally admits that a tenant lives with her, but he remains elusive. Vanessa's dubious explanations do not satisfy Sybille and only add to her curiosity.

Édouard's life is starting to unravel as the awful truth comes out. Benoît makes some startling revelations to Sybille, but she is not entirely surprised. It's not all gloom and doom for her, however, as an old flame is rekindled between them...

Vanessa is coming over to Sybille's house, which is now Benoît's as well. They don't need to spy on each other anymore, but Vanessa is bringing her binoculars anyway. As for Édouard... justice has prevailed.

In part one of "Le Jour où tout a basculé: Nos bébés ont été échangés" (The Day When Everything Changed: Our Babies Were Switched at Birth), a family is in turmoil. Frédéric is very jealous of his wife Anne-Sophie and accuses her of having an affair with an old flame. Although all the evidence seems plausible, is there another explanation?

Anne-Sophie and Frédéric are at loggerheads and won't speak to each other due to the unexpected results of a paternity test. Anne-Sophie receives some news at the end of the video that suggests the situation will become even more complicated.

Anne-Sophie meets with Fred to tell him the bombshell news about the paternity test results. Will this bring him back home?

The private detective's investigation reveals that Frédéric and Anne-Sophie's daughter Manon was switched at birth with another baby. They are distraught and can't face telling Manon the truth.

Frédéric and Anne-Sophie meet Manon's biological mother Laetitia in a café under the pretext of a survey. Totally unsuspecting, she is in shock when she finds out the real reason for their visit.

While Anne-Sophie and Frédéric have a meeting with Manon's biological mother, Manon carries out her own investigation and finds the detective's report. By the time her parents come home, she's gone, and panic sets in when Frédéric discovers her farewell note.

After running away from home, Manon finally decides to come back, only to be confronted with Émilie, her parent's biological daughter. Fortunately, Émilie manages to rescue the situation and convinces Manon to stay and speak with her parents.

In this last segment of "Nos bébés ont été échangés," you will discover how the two families are coping with their shocking revelation. Manon will meet her biological mother Létitia and become friends with Létitia's daughter Émilie in the process.