B y eleven o’clock the following morning they had a bidding war on their hands.

The competitors were five in number and scattered around the globe—the Singaporean shipping magnate, the hotheaded sheikh from Abu Dhabi, a Swedish steel baron, the third-richest man in China, and a mystery buyer represented by a French art consultant named Stéphane Tremblay.

Monsieur Tremblay, Gabriel explained to Ingrid, was the former director of the paintings department at the Louvre. A very serious player indeed.

“He rang Peter van de Velde last night. Said his client has the hots for the painting.”

“How hot?”

“A hundred and twenty-five million. When the Swedish steel baron bid a hundred and thirty, Tremblay and his client immediately went to one fifty.”

With Gabriel’s permission, Ingrid unleashed the hacking malware Proteus on the art consultant’s phone, and by early afternoon she was sifting through his emails, text messages, and telephone metadata.

His clients included some of the wealthiest and most prominent collectors in France, none of whom appeared interested in acquiring a newly discovered Leonardo being offered for sale by a third-tier dealer in Amsterdam.

Tremblay’s mystery client was listed in his contacts only as Archimedes.

Their most recent exchange of text messages made it clear that Archimedes was in it for the long haul.

All this Ingrid explained to Gabriel after walking Irene and Raphael home from school.

They spoke outside on the loggia, where the panel was drying in the tangerine light of the declining sun.

The beautiful girl from Milan appeared to be eavesdropping on their conversation.

Her heavy-lidded eyes, with their mismatched pupils, tracked Ingrid’s every move.

“How much longer?” she asked.

“Two weeks, maybe three.”

“She looks nearly finished to me.”

“I’m sure she does,” said Gabriel. “But I still have a great deal of work to do.”

“Such as?”

“Several more layers of paint and glaze on her face. Then I have to make the painting appear as though it’s undergone a recent restoration.”

“What about the surface cracks?”

“I will apply a special varnish that promotes craquelure and hope for the best.”

“Hope?”

“I prefer to induce craquelure by baking a forgery for three hours at two hundred and twenty degrees Fahrenheit. But that only works for canvases, not walnut panels.”

“What happens if the auction ends before your painting is finished?”

“We will have a serious problem on our hands.”

“Surely there’s something you can do to speed up the process.”

“What do you suggest?”

“You’re the professional,” quipped Ingrid. “You tell me.”

Gabriel blew on the surface of the panel. Ingrid doubled over with laughter.

***

That evening the third-richest man in China raised his offer to $175 million.

The bidder known only as Archimedes waited only twelve hours before instructing his French art consultant, via a supposedly encrypted text message, to increase his bid to $180 million.

In an effort to determine Archimedes’s identity, Ingrid hacked his phone.

She reported her findings to Gabriel that afternoon.

She had to raise her voice to be heard over the whirring of the large fan in his studio.

“It’s clean as a whistle. Professionally clean, if you ask me. I can’t even figure out where he is.”

Whoever Archimedes was, he quickly found himself in a shootout with four determined adversaries.

Indeed, in the span of just forty-eight hours, a flurry of bids pushed the offer on the table past the $200 million mark.

By the week’s end, the third-richest man in China was in the pole position with a bid of $250 million.

Gabriel, as he labored to complete his version of the painting, feared the Leonardo might slip beyond his reach.

He had plenty of friends in high places in western Europe and the Middle East, but none in China.

If the painting ended up in the hands of a billionaire from Shanghai, it would likely be lost forever.

He was pleased, therefore, when the Swedish steel baron raised his offer to $275 million, which set off another round of furious bidding.

It was the hotheaded young sheikh from Abu Dhabi, scion of the world’s wealthiest family, who broke the $300 million barrier, only to be outdone when the buyer known as Archimedes bid $325 million.

If the deal were concluded at that price, it would make the Leonardo the second-most expensive painting ever sold, eclipsed only by the price paid at auction for the Salvator Mundi .

Archimedes’s art adviser, Stéphane Tremblay, made this very point in an indiscreet text message sent to his mistress, a curator of French School paintings at the Louvre.

As luck would have it, he also disclosed the identity of his client.

Ingrid delivered the news to Gabriel as he was standing before the painting, a hand to his chin, his head tilted slightly to one side.

“You’re absolutely certain it’s him?” he asked at length.

“Would you like to see the text message? The only thing missing was his patronymic.”

“It’s my understanding that he owns the largest villa in Antibes.”

“The most expensive too.”

“The perfect place to hang the world’s most expensive painting, don’t you think?”

“Second most expensive,” she corrected him.

“For the moment, at least.”

Gabriel said nothing more. He was staring at the portrait, his pose unchanged. The girl from Milan was staring at Ingrid.

“Is she finished?”

“Yes,” replied Gabriel. “I believe she is.”