Mehmed II solidifies his reign, but in nearby Wallachia, childhood friend Vlad the Impaler gains notoriety and seeks to challenge Mehmed's hegemony.

Mehmed sends Maria to coax Hungarian King Matthias Corvinus into an alliance. An epic battle along the Danube River looms, and Vlad has the upper hand.

Mehmed's troops advance into Wallachia, and Vlad employs guerrilla tactics to weaken his rival. A threat lurks in the imperial palace.

4. Brothers No More As the war drags on and resources dwindle, Vlad wages biological warfare on Mehmed's army. Radu closes in on Vlad's castle to take Anastasia hostage.

Mehmed prepares to strike a fatal blow to Vlad's army. A spy is found in Mehmed's camp. Vlad launches a nighttime attack, but a surprise awaits.

Vlad and Mehmed face off. Maria and Gülbahar foil the Wallachian plot. Ottoman troops march into an abandoned Târgoviște and face a gruesome sight.

Mehmed launches an ambitious siege to break through the walls of Constantinople, but Giustiniani's mercenaries manage to forestall the Janissaries.

Mehmed's men dig underground tunnels in an attempt to shatter city walls. The tides turn against the Ottomans when a naval blockade founders.

Amid a spiral of brutality and low morale, Mehmed makes Giustiniani an enticing offer. The grand vizier urges Mehmed to seek a truce with his rival.

After claiming the Ottoman throne, Mehmed II sends an unmistakable signal to Byzantine emperor Constantine XI. Enter Genoese mercenaries.

Mehmed moves his ships overland to the Golden Horn in a daring, visionary feat. In the shadow of betrayal, Giustiniani attacks the Ottoman fleet.

Ottoman cannons reduce the city walls to rubble, and Venetian reinforcements arrive too late. Mehmed ushers in a new era for the Ottoman Empire.