A trainee is found dead in the huge organ of the Maison de la Radio. Astrid and Raphaëlle investigate the very heart of the instrument and meet an organist prodigy and her cantankerous old teacher. Things get tough when a second lifeless body is found near the organ. The modus operandi is the same... A track is beginning to emerge: what if it was the music that kills?
In search of medical attention for Ash, the Hemlock makes a stop on Candy's home planet of Skov. However, their new destination is in some trouble.
It's the end of the road for Seong-cheol and the team as they agree to shut down their operation. Do-gi is made to face the demons of his past.
For Mother's Day, the Chicken Squad watches their younger siblings to give their mom the day off.
Coop gets a taste of his own medicine when he wants to be Captain Tully's shadow.
Isabel and Nieto investigate a new attack. The terrorist Basauri was brutally beaten after being released. The rapist Haro takes advantage of his new freedom to spy on Isabel's life.
Many prisoners convicted of rape, murder and terrorism are released before serving their full sentences. Hours later, one of them is killed. The detectives Mora and Nieto take on the case.
The police investigation of the murders becomes complicated. Haro's plans start to impact Isabel's life, and her mental stability is about to be put through a terrible test.
The killer acts again, but this time, they lose their mask while escaping. The released prisoners start to protest in front of the police station and demand police protection.
Worried by Isabel's mental health, Nieto tries to find a way to keep her away from the Parot case and not expose her to so much pressure.
Thanks to Nieto's investigation, the police discovers the identity of the murderer of the released prisoners and communicates it to the media. Haro contacts Isabel and forces her to meet with him.
The avenger commits another murder and Nieto continues to investigate despite the Commissioner's reproach. Haro participates in an interview with Ana to clean up his image in the media.
Despite the Parot case being assigned to another detective, Nieto pursues a new line of investigation on his own while Isabel tries to adapt to her new life in a mental institution.
Nieto desperately strives to find evidence and prove that the young police officer is the victim of a plan against her. Haro secretly approaches Sol to execute the last step of his revenge plan.
The investigation takes Nieto to the city zoo. Somebody has freed all the monkeys from their cages. Haro continues playing with Isabel's mind.
Shax's CEO Park Jin-man forces the group to appear on a music show, despite their pledge to do otherwise for their juniors' sakes. The move leads junior artists, including Tea Party, to have shorter screentimes. Yu-jin confronts Ryok about the situation and is chastised for being rude to a senior in the industry. However, Tea Party earns a taste of popularity after skillfully performing their debut single a cappella when a technical glitch cuts out their music. Ma-ha fills in the vacated female lead role in a film Ryok is starring in and joins in a tour across major cities to promote the film's premiere.
Dami is shocked knowing that she could die if she fails to get the fox bead out of her body within a year, and Woo-yeo writes a contract to protect Dami and the bead. Dami struggles to survive in college among Tiger men.
Chris, Wes and Alex convince Eric to get a dog for his girlfriend. Chris reads people's minds and Eric rolls trick shots in a bowling alley.