“Yes, my dear?” he began.

And then he saw me and Tom.

He slumped in relief, and some of his years melted away. He reached for us, took our hands, and held them. “Boys,” he said, voice thick. “I had feared…”

We hugged him, and it felt like coming home.

Isaac could hardly believe he was seeing us again. “When I ended my quarantine,” he said, “I sent a courier to Blackthorn. He told me it had been abandoned. So I sent him to Tom’s house, and he saw the cross, and… I thought…”

I’d forgotten about that. The red cross of the plague had been painted on Tom’s door. With his family still on the boat, no one had returned to remove it.

“We were spared,” I said. “You didn’t find us because we weren’t in London.”

He was surprised at that. “Where did you go?”

“We should talk inside,” I said. “It’s quite a story.”

With the front door locked again, I introduced him to Sally. “She’s one of us,” I said, and he caught my meaning: We had no secrets.

Isaac took us upstairs, to his quarters above the shop. Although he seemed rejuvenated by our return, he moved awfully slowly up the steps. Delicately, like a man in constant pain.

As they were too narrow for either Tom or me to walk beside him, Sally lent him an arm, which he patted gratefully. He leaned on her all the way up.

His quarters were simple, just a kitchen and a bedroom. The real space was deep below the shop, in the secret library, which had once been a Templar sanctuary, centuries ago. Isaac put on a pot of coffee to brew.

“How I missed this,” he said wistfully as the aroma of roasted beans filled the room. “Quarantine living, as you might imagine, has very few charms.”

He listened, then, as I told him everything that had happened since he’d gone underground—and I did tell him everything, because Isaac and I had no secrets, either. He was saddened to hear of Dr. Parrett’s death, even more of Marin Chastellain’s. But he was delighted about our pensions and intrigued by my new position as apprentice spymaster.

“Benedict would have approved,” he said.

“You really think so?”

“You know his penchant for secrets. He was never a spy’s apprentice, of course, but his skill with codes was widely known. He even worked, for a time, with the spymaster of Charles I, when he was younger. The man sent him ciphers, and he’d send them back solved, if he could. He stopped with the coming of the Commonwealth; he disliked how they treated our previous king. But he started up again once Charles took back his throne. He might even have corresponded with your new master—what’s his name again?”

“Lord Walsingham.”

“Yes, that’s him.”

I was surprised the spymaster hadn’t mentioned it.

“So,” Isaac continued, “you learn more about codes, but still get to be an apothecary in the end? His Majesty has looked after you quite well, I think.”