I took a last quick glance around. No one was watching. I was sure no one saw as, with a swift movement, I pocketed the letters.

The autumn wind was gusting hard, dancing the dust around the square. It smelt of smoke – not Paris smoke, but the smoke of my childhood, not often remembered – a scent of incense and frangipani and fallen leaves. There are no trees on the Butte de Montmartre. It’s just a rock, its wedding-cake icing barely concealing its essential lack of flavour. But the sky was a brittle, eggshell colour, marked with a complex pattern of vapour-trails, like mystic symbols on the blue.

Among them I saw the Ear of Maize, the sign of the Flayed One – an offering, a gift.

I smiled. Could it be a coincidence?

Death, and a gift – all in one day?

Once, when I was very young, my mother took me to Mexico City, to see the Aztec ruins and to celebrate the Day of the Dead. I loved the drama of it all: the flowers and the pan de muerto and the singing and the sugar skulls. But my favourite was the piñata, a painted papier-mâché animal figure, hung all over with firecrackers and filled with sweets, coins and small, wrapped presents.

The object of the game was to hang up the piñata over a doorway and to throw sticks and stones at it until it split open, releasing the presents inside.

Death, and a gift – all in one.

It couldn’t be a coincidence. This day, this shop, this sign in the sky – it was as if Mictecacihuatl herself had put them in my path. My very own piñata—

I turned away, smiling, and noticed someone watching me. There was a child standing very still about a dozen feet away: a girl aged eleven or twelve, in a bright red coat, with slightly scuffed brown school shoes and flossy black hair like that of a Byzantine icon. She looked at me without expression, head cocked slightly to one side.

For a moment I wondered if she’d seen me take the letters. Impossible to know for sure how long she’d been standing there; so I just gave her my most appealing smile and pushed the bundle of letters deeper into my coat pocket.

‘Hello,’ I said. ‘What’s your name?’

‘Annie,’ said the girl, without smiling back. Her eyes were a curious blue-green-grey; her mouth so red it looked painted. Striking in the cool morning light; and as I watched, her eyes seemed to brighten still further, to take on the shades of the autumn sky.

‘You’re not from here, are you, Annie?’

She blinked at that; puzzled, perhaps, at how I knew. Paris children never talk to strangers; suspicion is hard-wired into their circuitry. This girl was different – wary, perhaps, but not unwilling – and far from impervious to charm.

‘How do you know?’ she said at last.