Catherine did not know that her husband was planning to reunite with Madame de la Rue. Nor did she know that Dickens had made a private arrangement with his “patient”: he would concentrate for one full hour on mesmerising her in his imagination starting at eleven AM each day. Madame de la Rue, far away, concentrated on receiving the radiation of Dickens’s Magnetic Influence as he turned his “Visual Ray” in her direction.

They were travelling by carriage—Catherine riding atop the vehicle for air, Dickens within—when eleven AM arrived and Dickens began concentrating on his distant patient. He had no sooner begun visualising his mesmeric hand passes and directing the magnetic fluid when he heard Catherine’s muff fall from the box above. Catherine, having no idea that Dickens was sending magnetic influences into the air towards Genoa, nonetheless had gone into a violent mesmeric trance on the carriage box above him, her eyelids quivering in a convulsive manner.

By the time the Dickenses had settled in Rome, the separation of the patient from her Magnetic Doctor had led to serious setbacks. Emile wrote that the Phantom showed signs of reappearing and taking control of Augusta. “I cannot beat it down, or keep it down, at a distance,” Dickens wrote back. “Pursuing that Magnetic power, and being near to her and with her, I believe that I can shiver it like Glass.”

The de la Rues appeared in Rome soon after this—to Catherine’s great astonishment—and Dickens resumed the daily sessions, now magnetising her, he wrote, “under olive trees, sometimes in vineyards, sometimes in the travelling carriage, sometimes at wayside inns during the midday halt.”

It was during this time that Dickens reported to Emile that Madame de la Rue was showing disturbing symptoms. “She was rolled into an apparently impossible ball, by tic in the brain, and I only knew where her head was by following her long hair to its source.”

It was at this point that Catherine (who had become pregnant again in late January, about the time she joined Dickens in climbing Mount Vesuvius as it was in full eruption) announced to her husband that she was distressed by the apparent impropriety of Charles’s relationship with Augusta.

Dickens, as he always did when accused of something, became furious and railed at Catherine that her accusations were absurd, even obscene, and that it was obvious to everyone else involved and uninvolved that his motives were absolutely the pure concern of a doctor of mesmeric magnetism towards one of his most troubled patients. Dickens shouted, berated Catherine, and threatened to leave Rome without her.

Nonetheless, a three-months-pregnant wife—especially one standing as firm in her position as the Great Wall of China—is hard to bully.

For the first time, Catherine had spoken out against one of Dickens’s obsessions and flirtations, and for the first and only time, he had relented. He explained to the de la Rues that Catherine was upset at the amount of time he was spending with his patient, but he also apologised profusely for Catherine’s attitude, calling her oversensitive to her own needs and insensitive to others’.

And Dickens never forgot or forgave this insult to his honour. Years later, shortly before he cast Catherine out of the house after the incident of the Ellen Ternan bracelet, he brought up what he called her irrational jealousy from fourteen years earlier and the effect such an insult had on him. “Whatever made you unhappy in that Genoa time had no other root, beginning, middle, or end, than whatever has made you proud and honoured in your married life, and given you station better than rank, and surrounded you with many enviable things,” he flung at her.

She had seen his relationship with poor, bedevilled Madame de la Rue as something suspect. Dickens informed her years later that she should have known—had she been a good and true wife she would have known—that his helping the poor woman had been the purest expression of his own innate creativity and nobility. His ability to mesmerise others, much like his ability to write great novels, was part of the firmament of character that was his greatest gift.

But now Dickens the minor master of Magnetic Influence had met the ultimate Master.

As I finished my breakfast at the club and folded my newspapers and left my napkin on the chair and found my hat and cane and went to the door, I had no doubt whatsoever that Dickens had been travelling into London every week on the train that terrified him into sweats to learn more about mesmerism from someone.

And it seemed to make sense that this someone was named Drood.

WELL, MR COLLINS. What a pleasant coincidence,” said a brusque voice behind me as I walked up Chancery Lane towards Lincoln’s Inn Court.

“Mr Field,” I said, half-turning and nodding but not stopping, omitting the “Inspector” before his name by choice.

He either did not notice the omission or pretended not to. “It is a lovely autumn day, is it not, Mr Collins?”

“It is.”

“It was a pleasant day yesterday as well. Did you enjoy your outing to Chatham and Gad’s Hill?”

I double-tapped my stick on cobblestones. “Am I being followed, Mr Field? I thought you had a boy waiting on Melcombe Place and Dorset Square for any message I might want to send you.”

“Oh, I do, Mr Collins,” said Field, responding only to my second question. “The lad Gooseberry is there now, waiting patiently. He can afford to be patient, since I pay him to wait. My own profession does not allow for such patience without severe penalties. Time, as they say, is money.”

We passed through Lincoln’s Inn Fields. John Forster had lived here during his many years as a bachelor, and I always wondered if it was mere coincidence that Dickens had given the villainous lawyer Tulkinghorn in Bleak House Forster’s old address.

When we passed through the Fields and reached Oxford Street, we both paused on the kerb as some dray waggons rumbled by. Then we had to wait for a line of carriages. Field removed his watch from his waistcoat and checked it. “Eleven twenty-five,” he said. “Miss R— should be on the outskirts of London by now, on her way back to Yarmouth.”

I gripped the cane as if it were a club. “So you have people following all of us,” I said through gritted teeth. “If you’re paying your operatives to do that, Inspector, then you are wasting both time and money.”

“I agree,” said Field. “This is why your information will liberate both of us from wasted time, Mr Collins.”

“If you had me followed yesterday,” I said, “then you know everything I know.”

Field laughed. “I can tell you the route you and Mr Dickens took on your three-hour walk, Mr Collins. But I cannot report even the gist of your conversation, although I know that the two of you were talking—or rather, Mr Dickens was talking—for most of the way back from Cooling Marsh.”

I admit that a flush of real anger crept up from my collar to my cheeks at hearing this. I did not remember seeing any other pedestrians during my walk with Dickens. Yet some blackguard had been hovering nearby the entire time. I felt guilty and exposed, even though Dickens and I had been doing nothing more sinister than taking an afternoon constitutional. And how did Field know that Martha had left on the 11:15 train, only ten minutes before the infernal inspector announced it to me? Had one of his operatives rushed pell-mell from Charing Cross Station to inform his meddling and blackmailing superior of this vital fact? Were his agents signalling to him even now from some alley in the direction of Gray’s Inn or Seven Dials? The anger continued to rise until I felt my heart pounding beneath my starched shirt.

“Do you want to tell me where I am headed now, Inspector?” I demanded angrily as I turned left and began striding briskly towards the west on Oxford Street.