The London fog was thick as wool pulled over the eyes when I stepped out of the station at the pleasant rustic hamlet of Hampstead. Streetlamps were already being lit, each surrounded by a saintly halo in the murk. I bought a paper from a decrepit scion of the lower classes and sat down on a bench to wait for my tardy associate.

"Watson!" hissed a voice through the gloom.

"Egad" I replied. "Where are you, Holmes?"

"I have just sold you a copy of the London Evening Standard. LATEST NEWS, GUVNOR! Though I had thought you might have remarked on my trombone."

I remarked on his trombone. "Good lord, Holmes! You have a trombone. Are you mad?"

"Not in the least. This is quite a singular trombone. It was discovered, twenty feet up in the branches of a tree, but otherwise almost entirely unharmed, a hundred yards from the body of the penultimate victim. It plays beautifully." He essayed a bar of Thaxted.

"An improvement on your violin, at any rate. And now, where is the last man to be murdered?"

Holmes led me with the accuracy of a homing pigeon through a white haze out of which trees drifted like gigantic submarine fauna. Finally, he came upon a spot where two policemen sat playing cards over the sad, torn body of one of our city�s street musicians.

"Evening, Mr. �Olmes", they chorused.

"Good evening, officers. Now, Watson, your medical training will almost certainly draw your attention to the body�s non-possession of a head. What I wish to know is, what removed that head so swiftly and so irrevocably?"

I examined the poor corpse as thoroughly as I could. "I have seen something similar to this at only one point in my career", I said. "An Indian mugger, not a man but a crocodile, which caused a commotion in our billet in Peshawar. One night, one of our subalterns, answering the call of nature by the waterside, was seized about a part of his anatomy I dread to name by the scaly abomination. Sixteen rifle bullets were needed to kill it, by which time the unfortunate officer was long dead. The brutes have jaws capable of cracking a man�s ribcage like an egg.

"Interesting. And what do you suppose did this?"

"Something, I would hazard a guess", I said, "with bigger jaws."

Holmes was striding out across the frozen grass, tapping his heel with his cane impatiently. "So, what do you suppose has bigger jaws than a crocodile?"

"I have no idea. An extraordinarily large lion escaped from a zoo, perhaps."

"Come here, Watson."

I walked closer. Holmes was standing over something, an impression in the turf.

"There. What do you imagine that is?"

I looked. Then, I stared.

"It's a footprint, Watson", said Holmes. "It is the footprint of a gigantic ten thousand pound theropod from Hell."