Someone had been selling invisible pets in Ankh-Morpork. Unfortunately, the truth of the matter was that these pets weren't real. Just empty collars and leashes. As his first assignment, it was up to Olaf to catch the offender.

My investigation began on a cold, damp Grune morning. A contact of mine had informed me that the phantom trader was operating near the Temple of Small Gods, and was keeping a low profile. I decided to go undercover and 'plain clothes' for this case (being a typical dwarf, that just meant removing my badge).

At first, there seemed to be nothing out of the ordinary near the Temple. The high priest of Um, God of Knotte Knowinge What To Do was running around, shouting a lot and looking confused. All seemed normal. I decided to mill around aimlessly for a while in the hope of a lead*.

Eventually, someone tapped me on the shoulder from behind. It was a very particular tap. It was the tap of a born predator. There could only be one person with a tap like that. "Ah, hello Mr Dibbler," I said, and turned round.

Cut Me Own Throat Dibbler looked a bit taken aback at first, but rallied well. "Psst," he managed.

"Psst?"

"Got a special offer for ya, mister. Just so happens I've got some of them trendy invisible pets in stock. I've got Concealed Cats and Disembodied Dogs. All the rage." He held a couple of empty leashes in the air and waved them around meaningfully. "Yours for only ten dollars, and that's cutting me own th..."

He didn't even get a chance to finish. I'd already stuck my badge under his nose and was reading him his Rights.

"Oi, 'ang on a moment," he protested, "I'm a fully paid up member of the Guild of CMOT Dibblers, got me license right 'ere."

"You're selling non-existant pets for Um's sake! That's fraud!"

"Not non-existant, invisible. Only person who can see 'em is Death 'imself. Can you _prove_ they don't exist? Eh? Eh?"

"What?"

"You 'eard me, Prove it! They're ethereal too, so you can stop aiming that spiked boot at Tiddles' head thankyouverymuch," he added.

I was tempted to fwap him with one of Mr Ironfoundersson's military baps, but thought better of it. He had a point. I was forced to admit defeat on this one for now, and walked away resignedly.

As I turned the corner into Quirm Street, I suddenly bumped into a seven foot black cloak with bones in it. Two blue specks of light peered down at me from under a hood. There was a scythe.

"Oh bugger," I thought out loud.

"G'DAY."

"N...Not my turn already, is it?" I quivered.

"NO. I'M ON HOLIDAY. SEEING THE SIGHTS. CITIE OF ONNE THOUSAND SURPRISIES AND ALL THAT."

"Ah," I replied, visibly relieved. "Hang on - if you're death, then how come I can see you?"

"PLOT DEVICE," said the apparition mysteriously.

"Oh. Er. Plot device? Fine."

All of a sudden, an idea hit me. "You can see everything, right? Even if it's invisible?"

"NOTHING EVADES THE GAZE OF THE REAPER."

"Mm. Can you come with me a moment? It's, um, touristic," I lied.

"DOES IT INVOLVE CATS?"

"Actually it does. Kind of."

"OH GOOD. I *LIKE* CATS. LEAD THE WAY."

I made my way back to the Temple of Small Gods. Dibbler was still there, feeding invisible cat biscuits to an invisible cat. He saw me, and sniggered. He then saw what was behind me, and screamed.

Regaining his composure a little, Dibbler pointed a trembling finger and mumbled incoherently.

"Don't worry, Mr Dibbler," I said, "he's on holiday. Off duty, you might say." This seemed to reassure Dibbler somewhat.

"WAIT A MINUTE," announced Death, "THERE AREN'T ANY CATS HERE. YOU SAID THERE'D BE CATS."

There was a pause.

"Damn," said Dibbler eventually.