'What happens to the books which are unpublished?' I asked wondering whether the characters in Caversham Heights really had so much to worry about.

'The failure rate is pretty high,' admitted Snell, 'and not just for reasons of dubious merit. Bunyan's Bootscraper by John McSquurd is one of the best books ever written but it's never been out of the author's hands. Most of the dross, rejects or otherwise unpublished just languish down here in the Well until they are broken up for salvage. Others are so bad they are just demolished – the words are pulled from the pages and tossed into the Text Sea.'

'All the characters are just recycled like waste cardboard or something?'

Snell paused and coughed politely.

'I shouldn't waste too much sympathy on the one-dimensionals, Thursday. You'll run yourself ragged and there really isn't the time or resources to recharacterise them into anything more interesting.'

'Mr Snell, sir?'

It was a young man in an expensive suit, and he carried what looked like a very stained pillowcase with something heavy in it about the size of a melon.

'Hello, Alfred!' said Snell, shaking the man's hand. 'Thursday, this is Garcia – he has been supplying the Perkins & Snell series of books with intriguing plot devices for over ten years. Remember the unidentified torso found floating in the Humber in Dead among the Living? Or the twenty-year-old corpse discovered with the bag of money bricked up in the spare room in Requiem for a Safecracker?

'Of course!' I said, shaking the technician's hand. 'Good intriguing page-turning stuff. How do you do?'

'Well, thank you,' replied Garcia, turning back to Snell after smiling politely. 'I understand the next Perkins & Snell novel is in the pipeline and I have a little something that might interest you.'

He held the bag open and we looked inside. It was a head. More importantly, a severed head.

A head in a bag?' queried Snell with a frown, looking closer.

'Indeed,' murmured Garcia proudly, 'but not any old head-in-a-bag. This one has an intriguing tattoo on the nape of the neck. You can discover it in a skip, outside your office, in a deceased suspect's deep-freeze – the possibilities are endless.'

Snell's eyes flashed excitedly. It was the sort of thing his next book needed after the critical savaging of Wax Lyrical for Death.

'How much?' he asked.

'Three hundred,' ventured Garcia.

'Three hundred?!' exclaimed Snell. 'I could buy a dozen head-in-a-bag plot devices with that and still have change for a missing Nazi gold consignment.'

Garcia laughed. 'No one's using the old "missing Nazi gold consignment" plot device any more. If you don't want the head you can pass – I can sell heads pretty much anywhere I like. I just came to you first because we've done business before and I like you.'

Snell thought for a moment.

'A hundred and fifty.'

'Two hundred.'

'One seven five.'

'Two hundred and I'll throw in a case of mistaken identity, a pretty female double agent and a missing microfilm.'