Dark Heart

A man was brutally murdered in an apartment. As the investigation began, another assault occurred shortly thereafter. The methods were similarly brutal, and both victims were pedophiles. While interviewing families who had been victims of sexual abuse, Will noticed that they all used the same phrase. He then discovered that similar assaults had occurred in the past, but the man claiming to be the perpetrator was currently serving a prison sentence.

Will began to suspect that his former boss was involved in an assault case involving a suspect accused of past child sexual abuse. During his active duty, Will had been in charge of investigating the man, who was currently serving a prison sentence. Meanwhile, the shadow of the serial killer looms over a newly released suspect accused of child abuse. Will realizes there is a connection within the police department. At the root of the case lay the “pain” and “anger” of the victims' families.

At the home of a nurse who died under mysterious circumstances on a subway platform, investigators discover unidentified bloodstains and a large sum of money she had been hiding. While Will is holding a strategy meeting, his nephew Harry is brought in. Realizing that his sister's fiancé, Paulo, is tormenting Harry, Will proposes a deal to Paulo. Meanwhile, the unidentified bloodstains are found to match the DNA of a boy who was declared missing 13 years ago.

Will finally tracks down Adam Miller, who was declared missing 13 years ago. However, Adam is on the verge of death after having one of his kidneys removed. The shadows of the Greek mafia and organ brokers loom over the series of incidents. Will turns his investigation toward those connected to Kyriacou, the second victim. Meanwhile, upon learning that Paulo is responsible for Harry's change in behavior, Will forces Paulo out of the picture…

A woman's body is discovered in a church. Someone had washed the body thoroughly, dressed it in brand-new clothes, and transported it to the church. Will finds this act of apparent care for the victim unsettling. According to the victim's colleague, she had been scheduled to do dangerous work on the day of the incident. Furthermore, the victim had just broken up with her boyfriend a few months earlier. Meanwhile, Harry calls Will, worried about his mother, who has been acting strangely.

[Season Final] Since the woman whose body was found in the church was a porn star, several men connected to her work emerged as suspects. However, with no solid evidence to go on, a voyeuristic video shot by a teenager turned out to be the key to the case. Just as the investigation was reaching a fever pitch, Will's sister, Juliette, suddenly vanished. As Will juggled the case and the search for his sister, his relationship with Sylvie began to fray…