The BBC broadcast and home media releases present the series in 12 parts, with the initial double-length episode titled "A Touch of Murder".
Claudius' life-long friend Herod has returned to Rome in time for Caligula's ascension.
Claudius humors him, hoping that Caligula will reveal his divinity to the Senate and be deposed, restoring the Republic.
Caligula also has Gemellus killed, removes Claudius from his position of consul, and declares his sister Drusilla his wife and fellow goddess Hera.
Disgusted with the depths of depravity that her family and Rome have sunk to, Antonia commits suicide, leaving Claudius distraught.