To the room, Simon says, ‘You must all be wondering why Isobel chose the six victims she did. To understand her choices, we need to look at the story she wrote and sent to Sondra Halliday: “The Dress”. You all assumed, and so did I at first, that all three stories Billy sent to Halliday were from the Stories of Enlightenment section of Lane Baillie’s website. When I looked, though, I only found two of the three. Whoever wrote the stories – and that’s not Lane; she only uses them – they’re obviously American. They write “realize” with a zed, and “color” and “favorite” without the “u”s.

‘I couldn’t find “The Dress” anywhere on the internet, and it contains only English words and spellings: “lift” instead of “elevator”, “pavement” instead of “sidewalk”, “colour” with a “u”. That’s because it’s the original work of Isobel Sturridge. It’s her murder manifesto. In it, she describes why she needed to kill, and how she chose her victims. It’s not a literal explanation – it’s all done metaphorically, but it makes it very clear why Isobel chose to kill the six people she did.’

Simon puts his phone, which he’s been clutching all this time, back in his jacket pocket. From the pocket of his trousers, he produces some papers, unfolds them and waves them in the air. ‘Anyone who hasn’t yet read it and wants to can read it. It’s about a dress that’s ugly and evil, but most people don’t realise. Most people think it’s beautiful, and all women start to buy it. They get away with buying the evil dress because they’ve fallen for it – they genuinely love it – but one woman, Perdita, buys it as a gift for her PA, though she personally hates it. The PA, Dolores, accepts the dress, though she loathes it too. And both of their hands start to ooze and seep with terrible sores. They’re mystified about why touching the dress has affected them both so badly when no one else has had that reaction.

‘Luckily, a sage is on hand to explain.’ Simon reads aloud. ‘“You gave something that you knew to be a vile thing to someone you care about,” the Sage tells Perdita. “You would never have bought one for yourself, yet you bought one for Dolores here. And you …” – here the Sage is talking to Dolores – “… you accepted this gift, though you didn’t want it and would never have bought one for yourself. You spotted its ugliness straight away, yet you accepted it. Both of you recognised instantly the horror of the dress, yet you said and did nothing against it … You acted against your own judgement and your own hearts. When we do that, we allow evil to prosper. That is why you have sore hands today.”’

Seriously? This sounds like a ludicrous story.