“So why were you sent, then?”

“Miss Band sent me as an exercise,” said Jocasta. “I say, these bricks really are jolly tricky, aren't they?”

“Yes,” said Vimes, “they are. Have you been rude to Miss Band lately? Upset her in any way?”

“Oh, no, your grace. But she did say I was getting overconfident, and would benefit from some advanced field work.”

“Ah. I see.” Vimes tried to recall Miss Alice Band, one of the Assassins' Guild's stricter teachers. She was, he'd heard, very hot on practical lessons.

“So…she sent you to kill me, then?” he said.

“No, sir! It's an exercise! I don't even have any crossbow bolts! I just had to find a spot where I could get you in my sights and then report back!”

“She'd believe you?”

“Of course, sir,” said Jocasta, looking rather hurt. “Guild honour, sir.”

Vimes took a deep breath. “You see, Miss Wiggs, quite a few of your chums have tried to kill me at home in recent years. As you might expect, I take a dim view of this.”

“Easy to see why, sir,” said Jocasta, in the voice of one who knows that their only hope of escaping from their present predicament is reliant on the goodwill of another person who has no pressing reason to have any.

“And so you'd be amazed at the booby traps there are around the place,” Vimes went on. “Some of them are pretty cunning, even if I say it myself.”

“I certainly never expected the tiles on the shed to shift like that, sir.”

“They're on greased rails,” said Vimes.

“Well done, sir!”

“And quite a few of the traps drop you into something deadly,” said Vimes.

“Lucky for me that I fell into this one, eh, sir?”