Heather pursed her lips. ‘I’ve been reading up on the subject – there are a lot of people on the internet who spend their time analysing these things. Anyway, the Grimms’ tales have mostly been Disneyfied these days, covered over with sugar and lace and made more palatable, but it seems that once they were every bit as unpleasant as the story Michael Reave told me. The thing is, the “Brother and Sister” story exists, except he’s changed the ending. In the real story, at the third stream the brother is turned into a deer. And then there’s a lot of quite complicated stuff about kings and princesses, and eventually the witch herself is torn apart by wild beasts. His version was a lot snappier, it has to be said.’

‘Oh.’ Nikki dipped another prawn cracker into the little plastic container of sweet and sour sauce. ‘Why do you think he changed it?’

‘Lots of these stories got changed, like I said, although not many were changed to be even more violent. Maybe he remembered it wrong, or maybe he was trying to tell me something.’ Catching Nikki’s raised eyebrows, Heather shrugged. ‘He said he’d told me that story to demonstrate that I don’t know everything about my mum. But maybe there was another message, too.’

‘That message might well just be “I want to freak you out”. Are you going to go back?’

Heather nodded.

‘He knows something, Nikki. He wasn’t surprised at all when I told him what happened to Mum. Maybe they had a pact or something, maybe they were writing in code in the letters.’ She trailed off, looking at the darkness outside the windows. ‘Whatever it is, I need to bloody know.’

Walking back to her mother’s house later, Heather found herself thinking of Michael Reave’s unpleasant fairy story again. It was true that her mother had been strict over her television and reading habits, to the point where Heather had often stayed late round friends’ houses, watching all sorts of horrors on VHS tape – the fact that her mum had banned them only made her more determined, obviously – and there had been an entire box in her wardrobe, carefully hidden under old shoes, containing books and comics her mum definitely wouldn’t have approved of. The idea that she had once collected especially ghastly stories, sharing them with a future serial killer, seemed impossible; a piece of a puzzle that would not fit together. Yet … there was something familiar about the story, even so.