As Eva gets closer to solving Matteo's case, she finds herself having to deal with a deep crisis with her husband Andreas. Paolo, meanwhile, makes important discoveries about the Monster.

One step away from solving the Monster's case, Eva and Paolo are diverted to the murder of a famous researcher. Like her colleague, Costa is also experiencing a moment of sentimental crisis.

Back to investigating the Monster, Eva and Paolo, closer than ever, put all the pieces together and begin to suspect that someone very close to them is hiding behind the killer.