[1][2] Alex Prevost – kidnapped, savagely beaten, suspended from the ceiling of an abandoned warehouse in a wooden cage – is running out of time.

Citing similarities to his wife's abduction and murder a couple of years ago, Police Commandant Camille Verhœven reluctantly accepts the case.

The futile interrogation at the crime scene yields no leads and he sends an indecipherable sliver of nameplate (of the van) caught on a CCTV camera to the forensics' team.

Upon recognizing the ambush set up by the police at his home, Trarieux makes a narrow escape and drives off to downtown Paris only to be cornered on a bridge.

They think of a possible link between Pascal's disappearance and Alex's kidnapping and interrogate the people with whom Trarieux had established communication prior to the abduction.

Pascal's body had been scoured by sulphuric acid and Camille recollects two other deaths with a similar Modus operandi and postulates that Nathalie/Alex could have been a serial murderer.

Part II Verhœven convinced of Alex's involvement in the preceding two murders, interrogates the relatives of the victims - Stefen Maciak and Brenard Gattegno.

Part III The hotel staff who discover Alex's body recounts seeing her dumping her belongings in a bin in the parking lot.