The rumbling had turned into loud thunder, and the first raindrops fell from the sky.

"Come upstairs," said Adami, "we'll talk inside." Adami could clearly see how much the Italians hated rain.

"Can you just go in there?" Nikki wanted to know.

"Yes, I know the janitor and Hall Five Hundred is being renovated. We can talk there in peace."

Elizabeth looked briefly at David's statue as they entered the palace. Pigeons fluttered around them.

Everyone knew the story of the little shepherd boy David fighting the giant Goliath. The unique thing about the story was that David was a novice in the art of war - if he had known what he was getting into, he would probably never have gone up against Goliath. Since he was unfamiliar with war, he did not choose a typical sword for battle, as the other warriors of King Saul would have done, but the only weapon he knew was the slingshot. Interestingly, this was also the only weapon with which David could defeat the giant Goliath from a safe distance. This is probably why the city of Florence chose David as a mascot and placed him directly in front of the town hall, the Palazzo della Signoria.

They entered the Hall of the Five Hundred inside the palace. A man in blue robes was driving a cleaning machine across the marble floor. On the walls were murals by Michelangelo and Leonardo, but they had never been finished. Savonarola had had them made before his idea for Florence had also come to an end, and he had first been hanged and then burned to death after trying to establish a dictatorship of virtue in Florence, which had, of course, gone entirely wrong.

She briefly updated Adami on the story about Carina, the kidnapping, and the fact that Ottavio was the only one left.

"We really need to talk to him," Nikki said with a frown.

Adami pursed his lips and nodded. "Will his car do?"

The officer tucked her chin. "Why?"

Adami lifted his cell phone. "A text just came in," he said. "Donatella's lawyers had already told me they hadn't been able to reach him, and now his car has been found."

Nikki closed her eyes for a second. "Where?"

"They found his Ferrari south of Florence on a feeder road. A tire had blown out about five hundred yards from where it had broken down, long crow's feet down the road."

Elizabeth took a deep breath. "So someone helped it along?"

"Apparently, someone helped it along so Ottavio would break down and be forced to stop."

"Quite a lot of news for a few hours," Nikki muttered.

Adami pulled a letter out of his pocket. "But that's not all."

Elizabeth furrowed her eyebrows. "It's almost like Easter; we're always finding something new."

"Just not what we're looking for." Nikki looked at the letter in the transparent envelope. "Did it come for Donatella?"

"That's right," Adami said, nodding, "but there's not much in it."

Elizabeth looked at the card. "It looks like a mourning card."

"And it is. It arrived less than an hour ago."

"By post?"

"By courier. There was no return address, and the courier was paid in cash. Also, in Florence. But the store doesn't have a camera. So we don't know who posted the letter."

"Great," Nikki growled, "but it was only a few hours ago that Donatella announced her husband's death, wasn't it?"

Adami looked at her closely. "That's the strange thing. The card arrived almost at the same time as Visconti's death."

Elizabeth's gaze trailed over the paintings, following the man with the cleaning machine as he slowly dragged it along the corridor. "So the person who sent this card already knew about Visconti's death?"

Nikki looked closely at her mother. "Probably not," she added, "how would anyone know, and Visconti wasn't killed in public."

"That's right. And his death wasn't staged. Obviously, he didn't fall victim to the perpetrator who killed Donatella's daughter and her groom."

"Maybe she did?" asked Nikki. "Maybe she just threw the card in herself to distract herself."

Elizabeth furrowed her eyebrows thoughtfully. "Maybe, if it's from our killer, but was he trying to threaten Donatella? Or was the card intended for Visconti? The murderer couldn't have known that the old man was dying?"

Adami puffed out his cheeks. "True again."

Elizabeth looked at the two of them closely. "What was it like with Sherlock Holmes? If you take away everything that can't be, what's left is the truth. No matter how improbable it is."

Nikki took a step towards Adami. "What does the map say? That's the question that should be answered." She gave her mother a quick glance.

"The card has no return address, as I said, and it's written in red-brown letters again," he replied.

"Just like Turelli's."

"Exactly."

"And what does it say?"

Adami put on a pair of latex gloves and opened the letter. "Just this passage."

Elizabeth and Nikki bent over the letter.

El emperador del doloroso regno

"The emperor of the painful kingdom?" Nikki asked, her eyebrows furrowed. Outside, dark clouds were gathering, and thunder was thundering as if the gods of antiquity, who appeared with Dante one last time, were angry.

Adami looked at her and smiled. "Right! And then you say you don't know Italian?"

Nikki smiled as well. "Well, that's fine. It's probably from Dante."

"I assume so."

"Pain is a big theme in Dante, as far as I know," Elizabeth said with furrowed brows, "the primal pain is always the pain of Christ. Doloroso regno means something like the painful kingdom. The street in Jerusalem that Christ had to walk on with his cross was called Via Dolorosa."

Nikki took a deep breath. "Pain plays a role, of course," she said, "But the color --" She thought momentarily. "Maybe the letter also comes from the person who killed Turelli?"

Adami nodded slowly. "And then there's something else here. On the back."

What happens up in the cathedral will happen to you.

"What's that supposed to mean? And which cathedral does he mean?" Nikki wanted to know. "The Florentine cathedral, surely?"

"Possibly."

"But what happens there that is supposed to happen to the letter's reader?" The officer stepped to the side so the cleaning trolley could drive past them. "And who is meant by that anyway? Donatella or Visconti?"

Elizabeth took a deep breath. "There's only Donatella left now."

"If he really knows that Visconti is dead. Which the person, whoever that is, doesn't necessarily have to know."

Nikki gritted her teeth for a moment. "Fine. There's something at both Dante's and the cathedral that could threaten Donatella. We can go to the cathedral now --"

"... or we can ask someone who knows more," Adami replied with a shrug.

Elizabeth nodded slowly. "Navarro, of course; who else?"

"He's very close by," Nikki said. She seemed to be looking forward to another visit to the library.

Adami shook his head slowly. "He won't be back until tomorrow. He's at a conference in Bologna today."

Elizabeth looked closely at her daughter. "In the meantime, we can ask Nick if there's any way we can get a camera shot of the courier store via Europol. We've already called him."

Adami took a deep breath and nodded slowly. "It's worth a try."