THE INVESTIGATION ROOM IN the Iudex tower hadn’t gotten any cleaner in the last few days. If anything, it had gotten filthier, the reek of pipe smoke overpowering, the very air quaking with the fumes of clar-tea. As I staggered back into the room it hardly felt better than the fernpaper mill, shadowy and swimming with corpse-stink.

Uhad, Nusis, and Kalista all looked up at me as I reentered. Only Ana did not, lounging in her chair with a cup of wine in her lap, her expression brimming with barely restrained satisfaction. I hoped she could feel the glare I gave her.

“Well, Signum?” sighed Uhad. “Did you find anything?” His shivering eyes danced over me, then Miljin, then Strovi, taking in our expressions. “I rather think you did…”

I bowed and said, “Would you like the whole testimony, sir?”

“Of course.”

I started speaking, summoning up each memory, each turn in the road, each gate we tried—rather slowly, since I had not anchored the experiences with a scent—until I finished my tale.

But as I finished, the atmosphere in the room changed, and the three immuni—red, blue, and purple—all reacted.

Nusis’s usual helpful smile flickered, then melted, replaced by a look so grave it was like I was reporting her own death. Uhad put his cup of tea down far too hard, spilling the steaming black fluid over Kalista’s pile of parchments. Kalista herself coughed in the middle of a puff of her pipe, then spasmed, spilling the smoking weed over the table, where it died with a hiss in the spilled tea.

Then all was still. The only sound was the drips of tea on the floor. Ana’s triumphant smirk slowly faded as well, and she swiveled her head around as the silence continued.

She began to look alarmed. So I began to feel alarmed.

“You think…you think the Engineers were poisoned at the home of the Hazas?” said Uhad faintly.

He looked aghast. I wondered what to say. I had expected this news to be taken poorly, but not this poorly.

“And you’re sure this took place eight days before the breach?” said Kalista. She looked terrified. “The killer did the poisoning there? On that day? At that party?”

“Ahh. Party, ma’am?” I said, confused.

“Kalista…” said Nusis quietly.

I glanced at Strovi, who looked baffled. Miljin, however, looked bleakly amused.

Kalista stood up. “Should…should I get tested?” she cried. “Is there a test? I mean…Hell, do I have those spores growing in me now?”

“Kalista, if you’d been poisoned at the party, we would have known by now!” said Nusis.

“You mean I’d be dead now!” said Kalista.

“Well, yes, obviously!”

“But we don’t know how it works!” squawked Kalista. She clutched her clay pipe so hard it snapped in two. “We don’t know why it…why it took so long with the other Engineers! And oh, Sanctum, I’m an Engineer! They probably tried to do it to me, too, didn’t they?”

Uhad’s eyes shivered. He thoughtlessly lifted his empty cup of tea with one shaking hand and tried to drink from it. “I can recall…recall no staining of fernpaper during the occasion…No steam at all, surely…”

“I feel short of breath!” shouted Kalista.

“Kalista!” snapped Nusis. “Will you listen?”

“I feel a…a stiffness in my lungs, in my person, I…”

Ana stood up and clapped her hands twice, very hard. Everyone fell silent.

Then she stared around at them, turning to each of their faces despite being blindfolded. “So,” she said. “I take it there was an event of some kind at the halls of the Hazas, on this eighth night before the breach. A party. Yes?”

They all nodded.

I cleared my throat and said, “They have nodded, ma’am.”

“I see,” said Ana. “And…and all three of you were in attendance at this party? Do I have that correct?”

Kalista was so flustered she descended into frantic mutterings. But Uhad sighed and reluctantly said, “True. Yes. If only for a moment…”

“But we didn’t see any of those Engineers there!” said Nusis quickly. “If we had, we’d obviously have mentioned it!”

“Correct,” said Uhad. “Many of the upstanding members of the Iyalets were present at the Haza affair, not just us. And attendance is not uncommon. The gentry hold many events. Officers can decline some, but not all—and especially not those of the Hazas.”

“Specifics!” snapped Ana. “How many people came to this party? And during what times?”

“A hundred people or more,” said Kalista. “And it lasted hours.”

“Yet these Engineers were not present, of that I am sure,” said Uhad.

“How are you sure?” demanded Ana.

“We’ve been studying these people’s lives for the past days!” said Uhad with a sniff. “I would know if they’d been there!”

“But are you all even aware, Uhad,” she thundered, “of what the dead Engineers looked like?”

“I…I remember names!” said Uhad, affronted. “And I always make sure to get them, given my role.”

“And if they gave false names?” said Ana. “What then?”

“What is the nature of your tone here, Ana?” Uhad demanded. “It’s not like you think we killed those Engineers at this party?”

“I’ve no idea what to think!” said Ana. “But are you not cognizant, all of you, that you now seem to be witnesses to not only the poisoning and murders of ten Engineers, but also the inciting act that caused the greatest calamity of the recent imperial era? Have you not realized what this means?”

Another long, baleful silence.

“At the very least,” said Ana wearily, “it means we now have to get Commander-Prificto Vashta directly involved.”

Everyone looked shocked, myself included. We had not yet encountered something grave enough to call her in from her duties as seneschal of the canton.

“Why?” said Uhad.

“Because as I said, you are witnesses!” said Ana. “You cannot investigate yourselves! Nor can you question yourselves! Especially not if you all are seen to be in pretty good relations with the owners of the house where these people were originally poisoned!” She looked over her shoulder. “Miljin!”

“Yes, ma’am?” he said.

“Go with young Strovi here to tell Vashta we have urgent news. We will need her input to decide how to move further. Move quickly now! We must form a plan of action as fast as we can.”