Roman Empire 213 AD e. In the province of Tarracona Hispania, wealthy aristocrat Marcus Sertorius plans a military coup to dethrone Emperor Caracalla. To this end, he enters into an agreement with the Moors, but the condition of their military assistance is the delivery to the Moorish king of the priceless ruby “Heart of the Tiger,” kept in the treasury of Caracalla. In addition, Sertorius needs to bribe the legions stationed in Africa. He obtains money for this by seizing and selling the property of his debtors. One of these was the young aristocrat Aemilius Valerius Vestula, nicknamed Loredan. To get rid of him, Sertorius hires assassins, but when his plan fails, he sends Loredan to Rome on an errand that should lead the young aristocrat to death. Lots of adventures await Loredan, his faithful slave Narbo and friend Fabius: gambling, drinking and fights in taverns, houses of the rich nobility, the emperor's palace, dissolute women, sea voyages, the deserts of Libya, northern forests, battles with nomads and barbarians and, finally, a grandiose naumachia in the port of Alexandria!