No painting in the museum’s holdings answers to this description. Though the details she has provided are consistent with Raphael’s style, there is absolutely no corroborating evidence to support her claim, and it is likely that she has merely confused it with the Conestabile Madonna.

The radio fell silent at the beginning of the month and the last newspaper went to print on December 12. Even the bombing has stopped. There is nothing left now to distract them from the miseries of cold and hunger except their own internal resources. And so, as the world gets smaller and colder and dimmer, Marina notices, people are becoming fixated. Most fixate on their physical miseries, spending hours running their tongues over swollen gums or opening and shutting the same cupboard in search of food that is not there. But others disown their shriveling bodies and fixate instead on an idea.

Uncle Viktor has become increasingly obsessed with finishing his history of Urartu. He worries that he may die before he completes it, and that this unearthed history will die with him. Marina lies in bed late into the night and listens to the feverish scratching of his pen. It has gotten so cold in the cellars that ink freezes, and so he must constantly stop and warm the bottle in his hands. But then a few minutes later, the scratching will start again. Sometimes he writes late into the night until he collapses at his desk.

In another corner of Bomb Shelter #3, the architect Alexander Nikolsky also has his fixation. He sketches so incessantly that at the end of the day his fist will not unclench to release his pencil. The other night, he staged a showing of these drawings. He lined up chairs in his corner of the cellar, leaned one drawing against the back of each chair, and invited his neighbors to come view his work.

And when they came, what people saw was not art such as they had expected but drawings of the actual room where they stood. He had sketched interiors of the cellar and its residents, odd little drawings of their makeshift lodgings. Sketch after sketch showed the low vaulted ceilings crossed with pipes, the clutter of furniture, and the stark shadows cast by a single oil lamp. He had also sketched the rooms upstairs, some drawings all but black, others portraying eerily gothic scenes with figures dwarfed in huge, vacant spaces. One drawing showed merely a hand with three marble-size pieces of bread resting in the palm.

What struck Marina was the roughness of the drawings, their looming shapes and smudgy darkness. That and the human figures, faceless and interchangeable. She didn’t know if this was his intention, but they had the quality of nightmares.

Nikolsky pondered this. “My intention was not to suggest anything but what is. These are not meant to be art. They are documentation, so that those who come later will know how we lived,” he said.

Marina was reminded uncomfortably of her uncle recording the history of the lost civilization of Urartu.

“But surely,” Marina said to Nikolsky, “some here will live to tell the story themselves.”

“Oh, yes,” Nikolsky agreed pleasantly. “But who will believe them?”

Marina has her memory palace: that has become her fixation. She can now walk anywhere in the picture gallery, and the sculptures and paintings appear so readily in her mind that she can rattle most of them off without thinking. What started as an exercise, a distraction, has come to seem like the very point of her existence. But if she had to justify that point, she would be at a loss. There are no books, no drawings, nothing to show for nearly three months of practice.

“That is the point,” Anya says. “Your uncle and Alexander Nikolsky are wise men, I’m sure, but they trust too much to paper. No one can take away what is in here.” She taps her forehead.

“Yes, no one can take it away, but no one else can see it, either, Anya.”

“Don’t give up just yet, dear.”

Marina sighs.

One day shortly after they began their little tours, Anya stopped in the Titian Room, pointed to a place on the wall, and then, in a conspiratorial whisper, described a painting that Marina had never seen.

Anya breathed into Marina ’s ear. “They took it away.”

“Why do you whisper, Auntie?” Marina asked. “It’s not a secret that paintings went to Moscow. Everyone knows this.” About ten years ago, Stalin forced the Hermitage to send a large part of its holdings, including some four hundred old masters, to the Museum of Fine Arts in exchange for some Impressionists and Post-Impressionists which were too decadent to display. The professors at the academy used to talk quite openly about it, though of course they were careful to couch the rape of the museum in the most veiled of euphemisms.

Anya shook her head and whispered, “Not the paintings that went to Moscow. Others. Before that. Before you were born.” She glanced around again, as though someone might be hiding in the empty room. “They would come and the next morning things would be missing,” Anya said, raising her eyebrows knowingly.

“Who?”

“I never saw them, but it was well known that they were from the Antiquariat.”

According to Anya, all through the twenties, Stalin’s agents came to Orbeli with lists and left in the night with art to be sold on the international market. When the room attendants and museum guides came to work in the morning, they would find that art was missing and that the remaining paintings had been rehung in the night to disguise the gaps. Curators and directors made no mention of the vanished work and rebuffed any questions, and quickly it was understood that, officially, this art had never existed. Anya says that, years before the official deacquisitions, hundreds of other pieces disappeared one by one: paintings and sculpture and enough silver to fill a pirate ship.

But Anya can recall these paintings as easily as those that are still part of the collection, and she has come up with a scheme to include all these missing works in Marina ’s memory palace. Never mind that Marina has never seen them herself. This has become Anya’s fixation.

“If no one is left to remember them,” Anya said when she first hatched this lunatic notion, “then it is as though they never existed.”

Marina agreed that this was sad but protested the logic of trying to remember something she had never seen. But Anya was not interested in reason. “I could die any day now,” she answered, “and when I do, they should not die with me.”

It is impossible to argue, as she shows every sign of being near death. The many layers of clothing everyone must pile on against the cold conceal the worst ravages of starvation, but Anya is increasingly frail, hardly able to bear even the weight of her own bones. Walking tires her, and she can take only a few steps without having to rest. Her health alone would seem to be reason enough to abandon walking the palace and burning precious calories unnecessarily, but Anya is adamant, and Marina suspects that this need to pass on what she remembers is the only thing keeping her alive.

So now Marina is trying to relearn the rooms, adding another layer of vanished paintings over the ones she already knows. Anya describes the missing canvas in detail, and while Marina can’t actually visualize it, she commits enough to memory to appease her friend. It is tedious work, and even though they get up earlier and earlier, their progress has slowed to a crawl. They have not yet made it past the New Hermitage rooms or across the courtyard to the rooms in the Winter Palace, and some days they cannot even get up the stairs.

This morning, though, Anya is determined to visit the Rembrandt Room, where she says she has much to show Marina.

The Main Staircase inside the New Hermitage is treacherous with ice, and there are no handrails to prevent a fall. Anya leans heavily on Marina, and the two edge up one step at a time, like mountain climbers on a treacherous slope. It takes them half an hour to reach the top. They traverse the long landing, passing empty marble pedestals, and come to the first room beyond the staircase, where the van Dykes hung. Anya pulls a rag from the pocket of her jacket. She is loath to admit how exhausted she is, so while she rests she makes a show of inspecting a large frame leaning against the wall. She carefully wipes away dust that has settled along the top edge.