As Rome prepares for its Carnivale, vampire hunter Lady Victoria Gardella is in no mood for festivities. But her personal grief must be set aside for there is a sinister plot underway. In yet another play for power, vampires have formed an unholy alliance with the demon Akvan in order to gain access to an ancient alchemist's secrets. Reluctantly, Victoria must turn to the enigmatic Sebastian Vioget for help, just as Maximilian Pesaro arrives to assist his fellow slayers – no matter what the sacrifice. As the bloodthirsty army ravages the city streets, Victoria races to solve the age-old mystery – if she fails, the world is lost for ever.