Arthur Curtis went back to the office to draft a reply to Isaac Bell.

He unlocked his door and stepped inside. Hairs prickled the back of his neck. He slewed sideways, pressed his back to the wall, and slid his pistol from his shoulder holster.

“It is only me,” said the shadow sitting at his desk.

“Pauline, how did you get in here?”

“But if I had been Colonel Moran I could have shot you with my silent air gun. No one in the building would hear.”

“Who the devil is Colonel Moran?”

“He tried to kill Sherlock Holmes. Holmes arrested him.”

“I said, how did you get in here?”

She pointed at the window, accessed by an alley fire ladder, which Curtis occasionally used to leave the office undetected. “As Sherlock told Watson in ‘The Adventure of the Crooked Man’: ‘Elementary.’”

“Elementary? Here’s elementary.” Curtis picked up his telephone. “I’m going to call the cops and have you arrested for breaking and entering if you don’t get lost once and for all.”

“Guess what I found in the library about Clyde Lynds.”

Art Curtis felt his jaw drop. “How do you know that name?”

“It’s in the marconigram you received from the Mauretania. The one about Professor Beiderbecke and Krieg Rüstungswerk.”

“That marconigram was in code.”

Pauline shrugged. “It’s not a hard code.”

“YOU ARE UP TO SOMETHING.”

Marion braced herself against the movement of the ship and regarded Isaac Bell with a dreadnought admiral’s collected gaze. Her coral-sea green eyes, her loveliest feature, Bell thought, if forced to choose only one, shimmered with equal parts warm love and healthy skepticism.

“A picnic,” he answered.

“It’s midnight. We’re the only two passengers not seasick in their cabins. I see no wicker hamper. Though for some reason you’re carrying a camera.”

“It only appears to be a camera. Take my arm so we don’t fall down the stairs.”

The seas were heavy. The broad grand staircase swayed as the ship rose and fell with stately precision, but after twenty-four hours in a North Atlantic gale, they were getting the hang of it. Bell gripped the banister and they climbed together, gauging the pitch, compensating for the roll. At the top of the stairs, Bell led Marion through the vestibule into the First Class music room, a domed lounge with a thick floral carpet and brocaded furniture in hues of pink, blue, red, and yellow. The lights were low and it was empty of people but for a sleepy saloon steward standing by with a bucket of champagne anchored between a couch and a pillar. Bell tipped him, lavishly. “I’ll open it, thank you. Good night.”

The man left, smiling.

Marion said, “Now you’ll try to make me tipsy.”

“Would you dance with me?”

“Delighted. As soon as the orchestra arrives.”

Bell opened his camera case and wedged it in a corner of the couch. Marion leaned in close. Wisps of her golden champagne hair brushed his cheek. “What is that? Oh my gosh, a little gramophone. Where’s the horn?”