Detective Mehmet Süleyman arrives in Istanbul from England to join Superintendent Çetin İkmen's team. After a university student is found dead in a cemetery, Mehmet finds himself involved in his first murder investigation.
Suspicious messages found on Gözde's phone turn the spotlight on her secret boyfriend Kemal. The team interrogates Kemal and with the new information they get, they pursue another suspect.
The public murder of Demir, a music manager from one of Istanbul's most successful families, initially seems to be linked to his involvement in the music business. Meanwhile, Mehmet Süleyman reconnects with his father Abdel.
Convinced that Dillon or Cem is responsible for Demir's death, İkmen and his team are given 24 hours to identify the killer. Meanwhile, Mehmet Süleyman and Kemal take Leyla back to her old apartment, where they find a USB stick that, although unfamiliar to Leyla, she had obviously kept on purpose.
With İkmen on paternity leave, Ayşe begins investigating the death of a garbage collector in a poor neighborhood of Istanbul, and with the help of Mehmet Süleyman, she quickly realizes that this is not an isolated incident. A serial killer targeting garbage collectors is on the loose...
Mehmet Süleyman is sent undercover into the world of garbage collectors to get closer to the two remaining suspects. Meanwhile, Ayşe has to continue the Leyla case in Mehmet Süleyman's absence and goes to see one of Istanbul's notorious drug smugglers.
With İkmen's promotion, Mehmet Süleyman and Ayşe are sent to the scene of what appears to be an accident. However, Mehmet Süleyman quickly realizes that all is not as it seems and that the fire was deliberately set.
Leyla makes a discovery about Jakob, whom she recognizes by his orange hat from the night of the accident, but it is too late and they are both kidnapped....
