She was breathing. But her face was the blue-white of marble. I wondered briefly how long she had been there.

‘Mrs De Witt? Wake up! Oh, God … wake up!’

I ran around the apartment, looking for the phone. It was in the hallway, situated on a table that also housed several phone books. I rang 911 and explained what I had found.

‘There’s a team on its way, ma’am,’ came the voice. ‘Can you stay with the patient and let them in?’

‘Yes, yes, yes. But she’s really old and frail and she looks like she’s out cold. Please come quickly.’ I ran and fetched a quilt from her bedroom and placed it over her, trying to remember what Sam had told me about treating the elderly who had taken a fall. One of the biggest risks was their growing chilled from lying undiscovered for hours. And she felt so cold, even with the full blast of the building’s central heating. I sat on the floor beside her and took her icy hand in mine, stroking it gently, trying to let her know somebody was there. A sudden thought crossed my mind: if she died, would they blame me? Mr Gopnik would testify that I was a criminal, after all. I wondered briefly about whether to run, but I couldn’t leave her.

It was during this tortured train of thought that she opened an eye.

‘Mrs De Witt?’

She blinked at me, as if trying to work out what had happened.

‘It’s Louisa. From across the corridor. Are you in pain?’

‘I don’t know … My … my wrist …’ she said weakly.

‘The ambulance is coming. You’re going to be okay. It’s all going to be okay.’

She looked blankly at me, as if trying to piece together who I was, whether what I was saying made any sense. And then her brow furrowed. ‘Where is he? Dean Martin? Where’s my dog?’

I scanned the room. Over in the corner the little dog was parked on his backside, noisily investigating his genitals. He looked up when he heard his name and adjusted himself back into a standing position. ‘He’s right here. He’s okay.’

She closed her eyes again, relieved. ‘Will you look after him? If I have to go to the hospital? I am going to the hospital, aren’t I?’

‘Yes. And of course.’

‘There’s a folder in my bedroom that you need to give them. On my bedside table.’

‘No problem. I’ll do that.’

I closed my hands around hers, and while Dean Martin eyed me warily from the doorway – well, me and the fireplace – we waited in silence for the paramedics to come.

I travelled to the hospital with Mrs De Witt, leaving Dean Martin in the apartment as he wasn’t allowed in the ambulance. Once her paperwork was done and she was settled, I headed for the Lavery, reassuring her that I would look after the dog. I would be back in the morning to let her know how he was doing. Her tiny blue eyes filled with tears as she issued croaking instructions as to his food, his walks, his various likes and dislikes, until the paramedic shushed her, insisting that she needed to rest.

I caught the subway back to Fifth Avenue, simultaneously bone-weary and buzzing with adrenalin. I let myself in, using the key Mrs De Witt had given me. Dean Martin was waiting in the hallway, standing four-square in the middle of the floor, his compact body radiating suspicion.

‘Good evening, young man! Would you like some supper?’ I said, as if I were his old friend and not someone vaguely expecting to lose a chunk out of one of my lower legs. I walked past him with simulated confidence to the kitchen, where I tried to decipher the instructions as to the correct amount of cooked chicken and kibble that I had scribbled on the back of my hand.

I placed the food in his dish and pushed it towards him with my foot.

‘There you go! Enjoy!’

He stared at me, his bulbous eyes sullen and mutinous, forehead rippling with wrinkles of concern.

‘Food! Yum!’

Still he stared.

‘Not hungry yet, huh?’ I said. I edged my way out of the kitchen. I needed to work out where I was going to sleep.

Mrs De Witt’s apartment was approximately half the square footage of the Gopniks’, but that wasn’t to say it was small. It comprised a vast living room with floor-to-ceiling windows overlooking Central Park, its interior decorated in bronze and smoked glass, as if it had last been done some time around the days of Studio 54. There was a more traditional dining room, packed with antiques sporting a layer of dust, which suggested it hadn’t been used in generations, a melamine and Formica kitchen, a utility room, and four bedrooms, including the main bedroom, which had a bathroom and sizeable dressing room leading off it. The bathrooms were even older than the Gopniks’ and let loose unpredictable torrents of spluttering water. I walked round the apartment with the peculiar silent reverence that comes with being in the uninhabited house of a person you don’t know very well.

When I reached the main bedroom, I drew a breath. It was filled, three and a half walls of it, with clothes neatly stacked on racks, hanging in plastic from cushioned hangers. The dressing room was a riot of colour and fabric, punctuated above and below by shelves with piles of handbags, boxed hats and matching shoes. I walked slowly around the perimeter, running my fingertips along the materials, pausing occasionally to tug gently at a sleeve or push back a hanger to see each outfit better.

And it wasn’t just these two rooms. As the little pug trotted suspiciously after me, I walked through two of the other bedrooms and found more – row upon row of dresses, trouser suits, coats and boas, in long, air-conditioned cupboards. There were labels from Givenchy, Biba, Harrods and Macy’s, shoes from Saks Fifth Avenue and Chanel. There were labels I had never heard – French, Italian, even Russian – clothes from multiple eras: neat little Kennedy-esque boxy suits, flowing kaftans, sharp-shouldered jackets. I peered into boxes and found pillbox hats and turbans, huge jade-framed sunglasses and delicate strings of pearls. They were not arranged in any particular order so I simply dived in, pulling things out at random, unfolding tissue paper, feeling the cloth, the weight, the musty scent of old perfume, lifting them out to admire cut and pattern.

On what wall space was still visible above the shelves I could just make out framed clothes designs, magazine covers from the fifties and sixties with beaming, angular models in psychedelic shift dresses, or impossibly trim shirt-waisters. I must have been there an hour before I realized I hadn’t located another bed. But in the fourth bedroom there it was, covered with discarded items of clothing – a narrow single, possibly dating back to the fifties, with an ornate walnut headboard, a matching wardrobe and chest of drawers. And there were four more racks, of the more basic kind you would find in a changing room, and alongside them, boxes and boxes of accessories – costume jewellery, belts and scarves. I moved some carefully from the bed and lay down, feeling the mattress give immediately as exhausted mattresses do, but I didn’t care. I would basically be sleeping in a wardrobe. For the first time in days I forgot to be depressed.

For one night at least, I was in Wonderland.

The following morning I fed and walked Dean Martin, trying not to be offended by the way he travelled the whole way down Fifth Avenue at an angle, one eye permanently trained on me as if waiting for some transgression, and then I left for the hospital, keen to reassure Mrs De Witt that her baby was fine, if permanently braced for savagery. I decided I probably wouldn’t tell her that the only way I’d been able to persuade him to eat was to grate Parmigiano-Reggiano onto his breakfast.