A historical biography that chronicles the life of Osman bin Ertuğrul bin Suleyman Shah, the founder of the Ottoman Empire, which ruled various parts of the world for six centuries.
Osman Bey, who angered the emperor and Constantinople with his seizure of Kulucahisar Castle, brings peace to the end of the region. The Byzantine Emperor takes measures against Osman Bey.
In season three, Osman takes measures to arrest the priest Gregor, and new enemies ally against him, while he conquers the city of Yenişehir and kills the leader Romanos.
In season four, Osman continues to fight enemies and traitors, while his reckless young son refuses to remain under his leadership and seeks to reach power.
In season five, after several years have passed, Osman's sons grow up and become beys. He also expands his empire and strengthens his army, and his first goal becomes to conquer Bursa, while he enters into a conflict with the Sultan Yakup, who declares his rebellion.