The ancient city has been besieged many times over the centuries; but the cannons could not make a single breach in its strong walls, nor did the huge chain of the Golden Horn give way to the enemy ships. Moreover, if Mehmed wants to take the city, he has to fight not only against the Byzantine Empire and the Christian world behind it, but also against the mighty grand vizier Çandarlı Halil Pasha, his biggest opponent in the state.

After the death of Sultan Murad, Mehmed and Orhan take action. Like Mehmed, Orhan thinks he has a say in the throne. Orhan, who was held in Constantinople by the Ottomans, acts with the support of the Byzantines. Eleni, who is wanted to be forced into marriage with Orhan, also comes face to face with Mehmed in Edirne. Mehmed, who came to Edirne with the support of Mara Hatun, succeeds in sitting on the throne with the added strength of the principalities that joined him. Çandarlı Halil Pasha has nothing left to do but submit to Mehmed. Orhan, supported by the Byzantines, was late. Orhan, who became the target of Mehmed, cannot implement the plans of the Greek Emperor Constantine.

Mehmed prepares to take action for Constantinople, which he dreamed of after he ascended the throne. To this end, with the help of Zaganos Pasha, Şahabettin Pasha, Architect Muslihuddin and his mentor Akşemsettin, he prepares his plans for Constantinople behind the secret walls of the Ottoman palace. Mehmed, who hides these plans from Grand Vizier Çandarlı Halil Pasha and Ishak Pasha, is determined not to repeat the mistakes he made years ago. While preparing his plans for Constantinople, Mehmed needs the help of Eleni, the daughter of Mega Duke Notaras, who knows those lands best. Eleni, who wants to be a good architect, helps Mehmed with her confidence.

Mehmed and Delibaş, who came to Constantinople in disguise, came as a result of the monk Gennadios' call for help. Mehmed, who took action to prevent the Crusader Union from gathering, succeeds. The inability of the Crusader League to gather mobilizes the Byzantine Empire. The Byzantine Emperor Constantine, who learned that a Turk created chaos among the people and that the events developed as a result, pursues those responsible for this event. The doors of Constantinople are closed and everyone is questioned. Although it is thought that Mara Hatun, who came to marry the Byzantine Emperor Konstantinos, planned this event, the name behind the event is very different. Demetrios remembers telling the secret plan to Theodora, with whom he had a great crush. Pontus Princess Theodora keeps her mystery. Trying to reach Mara Hatun, who was brought to the Byzantine palace, Teodora reveals her true identity. So much so that the truth brings him face to face with Mehmed.

Sultan Mehmed Han learns that his brother Alaaddin was killed. Thereupon, he begins to investigate who the murderer in the palace is. Mehmed is aware that he is one of his closest friends. As a result of the trap he set, Mehmed learns that one of his right-hand men, Zağanos Pasha, did this. The reason why Zağanos Pasha did this is quite surprising. Because Sultan Murad thought of Alaaddin to succeed him on the throne. Mehmed must be killed so that the unrest between the brothers does not harm the Ottoman Empire. Zaganos Pasha, who wanted to prevent this, took action and poisoned Alaaddin. Akşemsettin allows Şehzade Orhan, who was caught in Constantinople, to escape. There is a completely different reason behind the scenes of this event, which Mehmed cannot make sense of. While dreaming of ascending the throne and conquering Constantinople for years, Mehmed became his student, groaning at the advice of his mentor Akşemsettin.

Akşemsettin, who expresses that fate has chosen Mehmed at every opportunity, increases the belief of Sultan Mehmed Han in himself. Mehmed calculates how he can conquer Constantinople with the help of Eleni and the pashas. As Mehmed prepares to attempt a move for Constantinople, Byzantine Emperor Constantine makes a plan in response to Mehmed. Konstantinos considers using Orhan as his last trump card. Konstantinos, who is planning to confront Mehmed and Orhan once again, is ready to do anything for revenge.