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.