Strike had turned his back on Vashti, and was looking at something in New Bond Street. His gaze, Robin saw, was fixed on the red letter box standing outside Russell and Bromley, its dark rectangular mouth leering at them across the road.

‘OK, let’s go,’ said Strike, turning back to her. ‘Don’t forget, you’re my sister and we’re shopping for my wife.’

‘But what are we trying to find out?’

‘What Lula Landry and her friend Rochelle Onifade got up to in there, on the day before Landry died. They met here, for fifteen minutes, then parted. I’m not hopeful; it’s three months ago, and they might not have noticed anything. Worth a try, though.’

The ground floor of Vashti was devoted to clothing; a sign pointing up the wooden stairs indicated that a café and ‘lifestyle’ were housed above. A few women were browsing the shining steel clothes racks; all of them thin and tanned, with long, clean, freshly blow-dried hair. The assistants were an eclectic bunch; their clothing eccentric, their hairstyles outré. One of them was wearing a tutu and fishnets; she was arranging a display of hats.

To Strike’s surprise, Robin marched boldly over to this girl.

‘Hi,’ she said brightly. ‘There’s a fabulous sequinned coat in your middle window. I wonder whether I could try it on?’

The assistant had a mass of fluffy white hair the texture of candy floss, gaudily painted eyes and no eyebrows.

‘Yeah, no probs,’ she said.

As it turned out, however, she had lied: retrieving the coat from the window was distinctly problematic. It needed to be taken off the mannequin that was wearing it, and disentangled from its electronic tag; ten minutes later, the coat had still not emerged, and the original assistant had called two of her colleagues into the window display to help her. Robin, meanwhile, was drifting around without talking to Strike, picking out an assortment of dresses and belts. By the time the sequinned coat was carried out from the window, all three assistants involved in its retrieval seemed somehow invested in its future, and all accompanied Robin towards the changing room, one volunteering to help her carry the pile of extras she had chosen, the other two bearing the coat.

The curtained changing rooms consisted of ironwork frames draped with thick cream silk, like tents. As he positioned himself close enough to listen to what went on inside, Strike felt that he was only now starting to appreciate the full range of his temporary secretary’s talents.