British detective Mehmet Suleyman arrives in Istanbul to join the homicide unit led by eccentric inspector Çetin Ikmen. As soon as he’s arrived, the team investigate the murder of a university student. To find her killer, the team must uncover the secrets of her double life, while Mehmet adapts both to his new life in Istanbul and to Ikmen’s unorthodox approach.

While the team close in on a suspect in Gözde’s murder, Suleyman pursues his private investigation on the side and discovers a mysterious name that he’s sure is somehow linked to what Leyla discovered before her fateful accident.

The murder of a rap music manager leads Ikmen and team to investigate intrigue and scandal in one of Istanbul’s richest families. Suleyman settles into Istanbul more and reconnects with his estranged father - but he continues to be frustrated in his search for Kayra Khan.

The Demir investigation feels like a wild goose chase until Ikmen decides to look much deeper into the past. Leyla begins to remember things from before her accident and presents Mehmet with a clue that could unlock the whole story of what happened to her.

In a poverty-stricken neighbourhood of Istanbul, a serial killer appears to be targeting rubbish collectors. With Ikmen on leave looking after his new baby, Ayse leads the investigation instead, and Suleyman finally entrusts her with the secret she’s suspected for so long.

With his family still growing, Ikmen decides it’s time to grow up a bit and seek promotion. Suleyman goes undercover as a rubbish collector to try and find the killer before they strike again, while Ayse turns to an unlikely old acquaintance for help.

When Ayse and Suleyman are sent to investigate a house fire, all seems innocuous at first, but they soon turn up a clue that may break new ground in Suleyman’s search for Kayra Khan. They’re even more surprised when the person who blocks them investigating it is the new chief inspector - Ikmen.

The team finally learn who is behind Kayra Khan, but bringing them to justice will be tough on everyone. Chief inspector Ikmen faces an uphill struggle to convince his superiors to commit to his plan.