Now Franck has found the five 1918 missing women's bodies and captive Mathilde in the cave, the procurer puts him back on the case officially. A notebook indicates the 1919 serial killer was Paul's grandfather, psychiatrist Adrien Creuzot, who treated all five, but died from Spanish flu in 1918 and had a hand amputated in the Verdun battles. Another granddaughter must be identified before the next copycat murder is expected in 48 hours. Franck still suspects Patrick Carbonnier, whose grandfather was falsely accused. Forensic expert Dr. Marion Ravel is another descendant, so Franck lets her move in for close protection, which soon turns romantic, until she discovers the resemblance with late wife Laura. Another severed hand is delivered, with a note "you're mine" signed A.C., in Mathilde's hospital, where an intruder kills uniformed cop Victor and her. Franck is arrested for all murders and suspected of Laura's death.
—KGF Vissers