All children of Umran and Ferit got married. They are now homeless and they start living with their children. The carelessness of their children will upset them.

Sultan Khan of Ottoman Empire has fallen in love with Princess Iren of Byzantium. When he asks her father Niktol for her hand he refuses and tries to kill Khan. The Sultan's armies then attack and overtake Constantinople (now renamed Istanbul). Niktol kills Princess Iren and flees with his army to the island of Lesbos. From Lesbos, Niktol launches a series of ruthless attacks on Turkish villages resulting in the death of one of the Sultan's guard's mother. The guard, Murat, is sent by the Sultan on a mission to avenge his mother's death and bring back the head of the man who killed Iren. Murat goes undercover in Lesbos posing as Royal Guard Kostas, seeking the killers.

Under the leadership of Sultan Mehmed the Conqueror, the Ottoman army captures one Byzantine territory after another, culminating in the conquest of Constantinople, which becomes the capital of the Ottoman Empire. During this time, Vlad the Impaler, the ruthless and notorious ruler of Wallachia, launches brutal raids on Turkish villages, ambushing and savagely killing Ottoman soldiers. To put an end to Vlad's atrocities, Sultan Mehmed tasks Hamza Pasha with confronting him. Vlad ensnares the Ottoman raiders, taking most of them captive, including the brother of Kara Murat. Kara Murat is coerced into betraying his master and is sent to the Ottoman palace as a spy.

Byzantine Prince kills Kara Murat's father and kidnaps his brother to raise him as the Black Knight to fight against Turks. Years later, Kara Murat has to face the notorious enemy in a mission to save abducted Karaca Pasha of Rumelia.

Four inseparable friends from childhood struggle in the best years of their lives when one grows up to become a prize fighter, second a police detective, third a nightclub runner and the fourth sets them all at loggerheads.