Episode 1
During a long summer’s evening two teenagers, who are becoming more than friends, take themselves off to a remote mountain sawmill where they know they’ll be alone. However, somebody else has the same idea and the boys end up secretly witnessing four murders. In order to hide their blossoming gay romance, the boys - Yann and Lucas - decide to remain silent about what they saw. Helene Siquelande, a former police hotshot who has decided to focus on her family, is assigned to the investigation. But she is also stepmother to one of the two teenage witnesses: Yann. The killer knows he was seen and sets out to track down the witnesses. The lies the two boys tell begin to snowball…
Episode 2
In nearby Perpignan, the killer sets a bomb in a nightclub owned by Milo Ubieta. Milo is the father of Lena, a wild teenager. With all the confusion surrounding the explosion, Lena manages to escape the apartment, where her father was holding her under lock and key. She sets off to meet up with "Lancelot". Helene Siquelande doesn’t believe in coincidences and now, with two major incidents locally - both with all the hallmarks of organised crime - she tries to establish if there are any links between the explosion and the mountain killings.
Episode 3
"Lancelot" is revealed as the mountain hitman. Lena, who was sleeping with him, is found dead. Yann and Lucas are beginning to feel out of their depth and panic when they receive pictures, taken the night of the mountain killings, that would expose their secret relationship. Is the killer blackmailing them? Knowing that the killer is on to them, Yann is scared for his life. Lucas, however, seems more concerned for his reputation and the repercussions of being forced to come out. The media coverage around the murders starts to ratchet up and the pressure begins to mount on Helene’s shoulders – but how can she solve the cases with so few clues?
Episode 4
Yann starts talking. Not enough to actually help the investigation, but enough to anger boyfriend Lucas, causing them to break up – and enough to upset his already delicate relationship with his stepmother Helene. While Helene is facing this major family crisis, she also gets humiliated professionally, when a young detective, Ronan Berg, comes in and takes over the investigation. But what Helene doesn't know is that the ambitious Ronan is actually "Lancelot", the very man she is hunting down and the killer desperately trying to find Yann and Lucas!
Episode 5
As Helene is fighting hard to keep Yann from leaving home, the investigation finally starts to throw up links and connections between the different killings. More significantly, crushed by the consequences of his web of lies - and to help protect Yann - Lucas confides in Helene and tells her that he alone witnessed the mountain killings. She believes him, especially as he presents her with the murder weapon. For the first time the investigation begins to leap forward. Concerned for his safety, Helene asks Ronan Berg if she can give Lucas police protection.
Episode 6
As the interest around the investigation grows and it becomes a national problem, Ronan Berg, aka "Lancelot" is forced into a major TV interview. Convinced that the two teenagers will recognise him during the broadcast, he gets rid of Lucas, the witness protected by the police. It now only remains for him to identify the second teenager, and then he’ll be off the hook. Helene finally comes to realise that the second witness that could identify "Lancelot" is Yann, her stepson! As he is in great danger, she decides to run away with her family...