Eugène Laborde turns to the GRDV following the disappearance of his granddaughter Manon, who has been missing for five weeks. As an adult, Manon is not being sought by the police, even though she vanished right in the middle of her bachelorette party. While tracing her steps, Esther, Frankie, and Douma find old demons resurfacing—putting Esther under immense strain. Meanwhile, Esther pursues the lead regarding Christophe Absi, convinced that Mathias had serious trouble with him. Tenacious, she is willing to do whatever it takes to make progress, even if it means clashing with her former colleagues and facing Douma's growing concern.

The GRDV reopens the case of Antoine—missing for fifteen years—after his mother claims to have seen him again recently. Esther, Frankie, and Douma investigate this unsettling reappearance, navigating doubt, uncertain leads, and buried truths. Meanwhile, Esther edges dangerously close to the truth about Mathias, while Théo pursues a lead on his own—at his own peril. Douma also discovers that Nawaz has gone missing, as Frankie faces a crucial decision regarding Boris. In a high-tension finale, events accelerate rapidly, and long-held certainties are shattered.