She slid out the metal rod that held the lid in place, reached into the basket, lifted out the cat, and put him down on Dirk’s desk, next to the basket.

Dirk looked at him.

He—Gusty—looked at him.

There is a particular disdain with which Siamese cats regard you. Anyone who has accidentally walked in on the Queen cleaning her teeth will be familiar with this feeling.

Gusty looked at Dirk and clearly found him reprehensible in some way. He turned away, yawned, stretched, groomed his whiskers briefly, licked down a small patch of ruffled fur, then leapt lightly off the table and started carefully to examine a splinter of floorboard, which he found to be far more interesting than Dirk.

Dirk stared wordlessly at Gusty.

Up to a point, Gusty looked exactly like a normal Siamese cat. Up to a point. The point up to which Gusty looked like a normal Siamese cat was his waist, which was marked by a narrow, cloudy grey band.

“The front half looks quite well,” said Melinda whatever-her-name-was in a small voice. “Quite sleek and healthy, really.”

“And the back half?” said Dirk.

“Is what I want you to look for.”

Beyond the grey, cloudy band there was nothing. The cat’s body simply stopped dead in midair. Everything below approximately the ninth rib was, well, absent.

The odd thing about this was that the cat seemed quite unaffected. This is not to suggest that he had learnt to live with his sad affliction, or that he was courageously making the best of things. He was, quite simply, unaffected. He didn’t seem to notice. Not content with ignoring the normal requirements of biology, the cat was also in clear breach of the laws of physics. He moved, jumped, promenaded, sat, in exactly the same way as if his rear half were present.

“It isn’t invisible,” said Melinda, picking the cat up, awkwardly. “It’s actually not there.” She passed her hand back and forth through clear air, where the cat’s hindquarters should have been. The cat twisted and turned in her grip, mewling crossly, then leapt nimbly to the ground and stalked about in an affronted manner.

“My, my,” said Dirk, steepling his fingers under his chin. “That is odd.”

“You’ll take the case?”