 Of all the secrets that lie buried with the dead, none is more challenging, none more tantalizing than the secret which the woman named Tofana took with her to the grave. To no one in her own time did she reveal it, and no one since has been able to find the key to it. But perhaps that is as it should be, for it is a secret which, if it were ever again unlocked, could only spread misery and death throughout the world. The woman, Tofana, was the resident of Palermo in the latter days of the 17th century. And it is no coincidence that it was those same days which witnessed a wave of poisoning that swept like a plague across the whole of Europe. The authorities were baffled. There can be no question that Pope was poisoned. He did not die a natural death. Not their colesterol, they know Lorenzo Costia, nor Alfonso de Cordova. No, I know. They were murdered, every one of them. We've examined their food, their wine, everything they took into their bodies for 24 hours before their death. We've never come upon a single trace of it anywhere. Not once did they discover any remnants of the substance that had caused death. And then, on the 10th day of August of that year, a man named Francesco Orsini, a poet and a philosopher, came to them in a state of great agitation. Gentlemen, you must have saved me. What is this paper you have? It was a slip under my door this morning. Let me see. Francesco Orsini, prepare yourself. At four o'clock in the afternoon of August 12th, you will die. They are going to poison me. Fortunately, they have forewarned us, so we can't prevent them. How? For the next two days, my dear Orsini, you will drink neither water nor wine. And you will eat no food whatsoever. And on the afternoon of the 12th, you will lock yourself in your study. One of my men will be with you to guard you. For two whole days, Francesco Orsini fasted. And at the appointed time, he was locked in his house under armed guard. I was in the room with him when it happened. Before I could send for help, he was there. It was not until months later that the woman, Tofana, was brought into the torture chambers to be questioned. They had reason to believe that she knew more than she admitted. And they had ways of extracting knowledge. Yes, it I will confess. You are, I believe, a brewer of poisons by profession? And then, when the poison they come to me... What do you call this concoction? You brew for that? It's called aquatofana. Why have we never been able to find traces of it? Because you look for them too late. If you wanted to see the poison that killed the pope in April, it would have to examine either wine in December. In other words, the action of the poison is delayed five months? Five months. Five a week or five hours. Whatever it desires. And how is it possible? What is the secret of this time potion? Can you kill me if you like? What are the secrets of my time potion by the wisdom? Yes, this was the aquatofana. The potion that had caused the death of no less than 600 men. A poison which could be so compounded as to cause death at any desired time after it had been administered. This was the secret which the fauna would not surrender even to those who tortured her. The secret which died with her. A secret incredible but true.