AN: Thanks to everyone who reviewed!
BekaJWP - Do you post on the Ankh-Morpork forum?
Tinúviel3 - I'll try to make them longer, but it seems to delete spaces between words every time I save it.
MK- You'll see now...

Chapter Four: Not of this Disc...

Ponder Stibbons took a deep breath, but almost whispered the words anyway. "An elf."
"An elf?!" Ridcully spluttered. "That's the best you can do? That, sir," he pointed at the Omniscope, "is one of the most devious, most evil, most self-centred creatures in the universe."
"The multiverse," said Stibbons, for emphasis as much as correction.
"An elf?" said Vimes flatly. "An elf took my son?"
"Yes!" said Ridcully and Ponder.
"But they're not real!" he exploded.
"Oh, they are," said Ridcully. "And we've met that one. She's their queen, she's the most dangerous of them all. Twisted. She was at the middle of that business in Lancre. Remember all those crop circles a few years back?"
"Yes, Sybil thought a dragon had slipped his collar," said Vimes, "but there were no- carry on."
"Well, that was her," said Ridcully. "They call it Circle Time up in the mountains. Something to do with universes touching..."
"And what would ... she ... want with my son?" asked Vimes icily.
"She likes children," said Ponder simply.
"Is he in much danger?"
"Oh yes," said Ridcully. "Absolutely."
"Lots," Ponder added fervently. "Though he should be all right for the time being."
"The time being?"
"Until she works out that he doesn't work like clockwork."
"So where is he now?"
Ponder glanced at his superior. "I can't be certain," he said, "but odds on... he's in another universe."
And then Carrot and Angua came in, closely followed by Lord Vetinari. Vimes stared.

"We came about the arrow," said Carrot, when Vimes took him aside, "but Lady Sybil told us about the - the other thing. She said you just ran off. Angua followed your trail, she said she couldn't find young Sam's."
"No," said Vimes bitterly, "she wouldn't. The wizards here have a theory about that. I wasn't sure about it until just now."
Carrot nodded. "This is the first place I would come, if Angua's nose failed."
"Those floorboards creak," said Vimes, shaking his head, "and Sybil was in the kitchen all morning."
"Yes," said Carrot. "She said."
"And what's his lordship doing here?" asked Vimes.
"I just had that meeting with him," said Carrot. Amazingly, he managed to avoid sounding reproachful. "I gave him Cheery's report. He said the arrow suggested some connection to the Agatean Empire because of the materials."
"Yes, Carrot, but why is he here?"
"Couldn't say, sir. He did say he wanted a look at the crime scene, but he arrived at the same time as me - Angua clacked me while Iwas at the Palace and I came straight here. I'll swear his coach never passed me by."
"Right," said Vimes.

It was not, of course, possible for anyone to get from the Palace to Scoone Avenue and back to UU before someone walked down to Sator Square, but his lordship had his funny ways.
Vimes had no doubt that Lord Vetinari had committed every inch of the crime scene to memory.

"...and some detailed, if eroded, designs on the tip," Lord Vetinari was saying."Ah, Commander."
In the meantime, Ponder Stibbons had set up another, bigger Omniscope, beside the one that rested on little Sam. He was sleeping. I'll find you, thought Vimes. I'll get you home, wherever you are. Then we can worry about who wants your dad dead.
"With respect, sir," said Vimes, "I have higher priorities at the minute."
"Yes, Commander," said Vetinari, "but the City does not. We appear to have the Agateans participating in an attempt on one of our nobles."
Vimes winced. Vetinari did so love to rub it in.
"And what do you make of... all this?" he gestured at the Omniscopes. Ponder was placing what seemed to be a splinter onto the sensor.
"I think it could prove useful," said Lord Vetinari. "Ah, it appears that we have found the origin of your arrow. Take it back, Mr Stibbons."

The image of a tree zoomed backwards. Now it showed a sapient pearwood grove facing the sea, now a peninsula, now a perfect map of Agatea.
"The south-east coast," nodded his lordship, "That would explain-"
Vimes snapped. "My son is missing! I don't even know if he's on the Disc! I- what?"
"Er, I just thought you might like to know," said Ponder, "he's not."
"Not what?"
"Not on the Disc. I zoomed out on him, too."
The group closed in around the smaller Omniscope. A vast expanse of land met their eyes, bounded by a coastline like none on the Discworld. Brown plains swept out westward; to the south was a huge gulf. The landscape was dominated and divided by mountain ranges.

Ridcully drew back first and cleared his throat. "And the young lad is there, you say?"
"Yes, Archchancellor," sighed Ponder, "I thought we'd agreed on that."
"Yes, capital, just checking-"
Ponder gasped. "Look! Something's drawing it away..." An eye rimmed with flames once again filled the screen. "It's the same place!"

And then a voice, a terrible voice that was not so much heard as felt, said, "Morgoth on a crutch!"