Isaac read it, disturbed. “What was the clue the Raven left?” he asked.

“I think it was a pigeon feather,” I said. “We found it tucked under Marin’s mattress. It had to have been placed there deliberately.”

“Do you know what it means?”

“I was hoping you would.”

He shook his head. “Benedict always kept pigeons, as you well know.” He nodded toward Bridget. “Beyond that? Nothing comes to mind.”

I told him we’d thought that Rémi was the Raven and described him. “Simon said he’s dead. But in the letter, the Raven claims Master Benedict was his enemy. Can you think of who that might be?”

Isaac mulled it over. “Hard to say. I don’t recognize Rémi’s description, but the man might have met Benedict years ago, so he wouldn’t look like he did last November. What’s more, he could have met him during his travels, maybe in France. I doubt I’ve ever seen him.” He regarded me. “You’re not certain this Rémi was the Raven, then?”

“I just want to make sure.”

“Understandable. Unfortunately, your description narrows down nothing. Your master made countless enemies over the years, some quite serious.”

“He did?”

Isaac smiled. “You loved Benedict, so you’re forgetting how abrasive he could be with those he thought ridiculous. He had many, many arguments with other apothecaries, physicians, even Parliament, about all sorts of things. The proper preparation of remedies, the care of patients, the management of outbreaks… Half of his opponents he thought quacks; the others, fools, and he was never shy about stating it. Being well respected—if not always well liked—meant he ruined many a reputation over the years. In London and abroad.”

“So we’ll never really know,” I said, disappointed.

“Not necessarily. Benedict kept detailed journals, all the way back to his own days as an apprentice. He’ll certainly have noted his nastier opponents—and it’s the pure viciousness in this letter that worries me. Perhaps we might find something there.”

I’d read some of Master Benedict’s journals before. One had even been a great help during the plague. “I have a few at home.”

Isaac nodded. “Benedict stored the rest downstairs, so I’ll have any years you’re missing. If you bring what you have to me, I’ll go through them in detail. See if anything sparks my memory.”

“We should work out this new message first,” Sally said.

Everyone agreed that was more pressing. Isaac studied the second letter, reading the line before the puzzle. “ ‘La ruota dell’italiano,’ ” he said. “You understand what it’s asking?”

“I have the device here,” I said, holding up the sack I’d brought from Blackthorn. “I can solve the code. It’s the riddles I don’t really understand. Not even the first one.”

I spread the letters out, and we looked at the first rhyming couplet.

An oath was made, a promise sworn,

To those who wished to bind him.

But he returned, and offered scorn,

And so they come to find him.

“Lord Walsingham thought that was a threat against the king,” I said.