A man is found by a dogwalker in a forest; his face severely torched, it seems he has been strangled to death, curiously he has the year 1991 carved into his chest. Days later a second victim is found also with a number carved into his chest - Does Antwerp have a serial killer? Where is Professor T when you need him?

With Daan fighting for his life in hospital, the search for the killer continues. Annelies meets with the widow of the third victim, urgently trying to find connections between the three murders. Unbeknownst to the team, he is much closer by than they could possibly imagine and has in fact already infiltrated the Department of Criminology.