The student leads her down service corridors-networks of narrow, windowless passageways with dim yellow lights and an endless string of doors without any identifying marks-so it's a mystery to Emily how he navigates through them. They enter the neurology department in two and a half minutes – the familiar break room, the cubbyhole, and the large space of the main part of the ward.

Emily enters Clark's office, holding her breath – if she had messed up or made a big mistake, she would have been reprimanded by either the attending or the head nurse, but not by the neurosurgeon: he has nothing to do with the junior staff, unless, of course, it was his own team.

Clark stands half-turned, his arms crossed over his chest, his white coat sloppily slung over his shoulders, his lips curved into a semblance of a smile.

Emily's spine sucked – fear mixed with a strange kind of awe. If it were Rebecca, she'd have pressed her lips together, relaxed her shoulders, and looked at the whole thing through a spiteful squint. But Emily isn't Rebecca; all she can do is wrinkle the already creased fabric of her gown and wriggle from foot to foot.

Of all the hospital's sixty-thousand-person staff, Miss Clark needed her.

Or…?

– Johnson," the neurosurgeon's heavy stare is almost physically palpable, "is our psychiatrist, Dr. Charles Clark.

Oh shit. Good thing she didn't say a word to him.

Her lungs run out of air as the student who called her here sits down on the padded couch and puts his leg over her leg; but-she's willing to swear! – at that moment, mischievous sparks flicker in his dark eyes.

The prank was undeniably a success.

Charlie had a mop of blond hair, ripped jeans, and a T-shirt with the Beatles emblem on it. Emily mentally excuses herself: Anyone would mistake him for a student intern; only the gray nametag that had fallen off his long robe gives him away as a doctor.

She looks closely: a long black Swatch strap, gray and blue Balmain, and a careless, as if intentionally placed blot on the lower left field of the robe – another famous logo, the name of which she does not remember. An envious sigh – in Britain, doctors are paid almost more than in other countries.

– Miss Johnson…

– You can just say Emily," the nurse says quietly, trying not to be distracted by her thoughts.

Are they brother and sister or husband and wife? Which one is older? And what is this woman's name anyway?

Why is she here…?

Charlie only silently spreads his hands as if answering unasked questions.

– Let's get right to the point. – Clark-whose-woman sits down in a wide, high-backed chair. – They say you spent the morning with a certain patient with a very strange diagnosis, right?

– But we didn't talk for more than half an hour. – Emily shakes her head. – I was only asking…

– You were talking about the mosaic. – Charlie leans his head back relaxed and looks up at the ceiling. – Just so you know, a mosaic, Emily, is part of a system.

– What system? – For the second time today, Johnson feels like a complete fool.

– Her memory, of course.

Everything Emily gives out in response fits into a simple, "Eh?"

– Our brain," Charlie explains patiently, "tries to cover the gaps in our memory with memories from nowhere. Or, if the trauma is too severe, it clings to words, places, actions-and inserts them like missing pieces.

– Like a mosaic," Emily guesses.

– That's right," the psychiatrist nods contentedly. – Her brain is clinging to two factors: it is you, Emily, and the puzzle. The puzzle. A fragment. A stumpy piece of life – whether past or present. And this idea-that she had something to do with it all-is now firmly planted in her head and taking root there.

– Like a virus?

– Exactly. Like a virus.

– She's about to have surgery. – It's like the neurosurgeon didn't even hear them talking. – We're gonna cut her head open again to see how she's doing. – A funny joke from her lips sounds like black irony. – She'll be conscious for a while, and Dr. Clark advises that you should be around. Maybe this way we can provoke… something.

– "Intraoperative brain mapping," Emily says in a cursory voice. Nightly vigils over textbooks have had their justifiable effect – Clark throws her a look full of surprise. I guess she's the kind of person who thinks all nurses are idiots.