Byron pored over it again. “‘Did you know that Franz Joseph Haydn had a brother? I used his work and Bach as inspiration... ’ Obviously, Bach is a reference to the motif. I’m certain Haydn’s brother is referring to the cipher you found in the encyclopedia. It was H.M.’s way of informing Mr. Harris the method of decoding the music, but he needed to be cryptic in case it fell into the wrong hands.”
Mira took the letter back from him. “If Mr. Harris regularly corresponded with this Mr. H. M., wouldn’t he already know the cipher?”
“Not necessarily. Not if H. M. determined that these papers were important enough to change the cipher. Evidently, Circe was aware of the situation, enough to know the package existed. H.M. may have added another layer of encryption so that, in the event that it was intercepted, the information would stay safe.”
“He must have encrypted it too well, in that case. Mr. Harrisworked on it for weeks and still didn’t decode it before he was killed. We have just over a day.”
“There must be something else.” Byron picked up the letter, standing and beginning to pace. “‘My dear niece, I know how much you enjoy Mendelssohn... ’ That’s another composer. Have we accounted for him?”
“One of his songs plays on the musical box that was sent with the sheet music.”
Byron rubbed his chin. “Why did H.M. send the musical box? It would have been much more expensive.”
“I wondered about that myself. Perhaps it was part of the cover? If someone opened the package looking for political documents, they would only find sheet music and a musical box.”
He hummed. “‘Book 1, Op 19b No. 1 in E minor—’” He stopped still. “E. You don’t suppose that’s the key, do you? Not musically, I mean. But that the cipher starts at E, not G?”
“Maybe?”
He rushed back to the low table, kneeling beside her. She handed him the pencil and they reworked the cipher together, heads close.
Once the adjusted cipher was written out they started at the beginning again, testing a few measures before moving forward to the measure after the BACH motif. Mira stood, pacing back and forth with the sheet music and reading out the notes as Byron translated them.
“D, F sharp, F flat, D flat, F sharp, D sharp, F flat—”
“Secret,” Byron whispered. “The first six letters spell secret.” He looked up at her, breaking out into a wide grin. A sensation of breathlessness came over her. They’d done it. They’d broken the cipher.
“Keep going,” he said, making a slash after the word.
“C flat, B, C, E, D flat, D sharp, B, F sharp—”
“Compartment. I would bet anything it will say compartment.”
“Let me finish the word!” she laughed.
They continued back and forth, with Byron reading out the words as he discovered them and Mira reading out the notes. After a point, he set down the pencil.
“Wait. Wait just a moment.”
“What is it?” she asked, turning towards him.
“It’s the musical box. That’s where the documents are!” He jumped to his feet, and before she knew it he had lifted her into the air, swinging her around. She dropped the sheet music in surprise, letting out an unladylike squeal.
He set her down, handing the now crumpled deciphered message to her.
Secret compartment, box, blue, horse, twist, use key.
He slipped an arm around her waist, pulling her close to him and kissing the top of her head. “We’ve done it. We’ve solved it!”
She laughed, looking up at him. “The musical box.”
He nodded. “The musical box.”
The two of them devolved into sleep-deprived giggles which were only interrupted by someone clearing his throat in the doorway.
“I’m sure this is all very exciting, but can you have some consideration for those of us who are convalescing?” Castel wandered in wearing a colorful dressing gown and a scowl. He held a hot water bottle to his head.
Byron bounded over to him. “We’ve figured out the cipher! Mary is safe. Regardless of what happens, she’ll be safe.”
