MONDAY MARKED the third week of Mr. Quisling’s cipher challenge. Nearly everyone had dropped out by now, having decided that doing homework would be easier than the work of creating and breaking the class ciphers. James and Maddie were both still into the challenge, but Emily figured it was more for the pride of winning their bet than for the homework passes at this point. The score was zero-zero, but at lunchtime James was confident that was about to change.
They sat at their table in the library, and James explained the mastermind code he’d come up with over the weekend, every so often looking over to where Maddie sat.
“I found this section about the Baconian Cipher,” James said. Emily leaned in to hear his whispered words.
“Bacon, like bacon and eggs?”
“Exactly. A cipher that tastes delicious on any sandwich.” James grinned. “No, Bacon was the guy who came up with it. With the Baconian Cipher, you use a combination of As and Bs to represent every letter of the alphabet. I was thinking about how computer programming is a type of cipher—it’s called coding after all—and then I came across this Baconian stuff, and it gave me the idea to combine it with binary code.”
“Binary what now?”
Instead of explaining, James pulled a sheet of paper from his binder and slid it over to Emily. A short paragraph typed at the top read: Beware the ninja monkey. He likes banana bread and drives a station wagon.
“This is a normal paragraph,” she said.
“Emily.” James tipped his head down. “You of all people should know normal-looking paragraphs can hide secret messages.”
“Oh. Duh. Well, how does this work?”
James pulled another sheet from his binder—the answer key, Emily presumed. Every letter of the alphabet was assigned a combination of ones and zeros:
a=00000
b=00001
c=00010
d=00011
e=00100
f=00101
g=00110
h=00111
i/j=01000
k=01001
l=01010
m=01011
n=01100
o=01101
p=01110
q=01111
r=10000
s=10001
t=10010
u/v=10011
w=10100
x=10101
y=10110
z=10111
“These zeros and ones are called binary. For this cipher, a different group of ones and zeros represent each letter—i, j, u, and v double up because they’re not used that much and it makes it more tricky,” James explained. “So I take my secret message, which is I like soup, and convert it to binary. So I is 01000, L is 01010, and so on, until you have this.”
James pointed to a paragraph on his answer key made entirely of 0s and 1s: 01000 01010 01000 01001 00100 10001 01101 10011 01110.
“Then I made up sentences that used at least as many letters as there are digits in this ciphertext. Beware the ninja monkey. He likes banana bread and drives a station wagon.” All the letters that represent zeros are in italics, so if someone knows what I’ve done, they could decode this. I still think it’d be pretty hard though.”
“This is so genius!” Emily said, a little too loudly. Maddie glared at them from across the room.
“Sorry,” she whispered to James. But it was shout-worthy. She never in a million years would have figured out how to decode James’s paragraph.
James dropped his pen on the cipher work and tipped his chair back. “No sorry needed. It will torture her to know she’s doomed. So what about the black cat phone number? Any progress?”
“If you consider progress figuring out what it’s not, then yeah, I made a ton of progress. It doesn’t have the right amount of numbers to be a license plate number, and it doesn’t work as an address for a location in San Francisco. Like: 97806797226 Forty-Ninth Street? You can turn it into a math equation, like add all the numbers to find a sum, but then what do you do with that? You just end up with another meaningless number.”
“Do you have it with you? I can take a stab at it—”
A hand reached in between them and grasped James’s copy of The Book of Codes from the table.
“I need to borrow this,” Maddie said. “We’re supposed to share. Library rules.”
James hastily slid his binder over his cipher pages before clamping a hand on the book to tug it back.
“That’s not a library book. It’s mine,” James said.
“Oh sure, like I’m falling for that.”
As James and Maddie tugged the book back and forth in front of Emily, the bar code waved like a black-and-white flag until it finally got her attention.
Emily pushed up from the table and shouted, “Stop!”
James and Maddie froze. Heads all around the room turned in their direction. The school librarian popped out from behind a bookshelf. “Is there a problem?”
Maddie pinched her lips into a pout. She looked from Emily to James then said, “No problem,” and flounced back to her table.
James warily watched the retreating mushroom head bob across the room. “Do you think she saw my cipher?”
But Emily was too focused on her discovery to pay attention to anything else. She tapped the bar code on James’s book.
“Look! Look at this!”
Above the bar code were the letters ISBN and a string of numbers that began with 978, just like the phone number. Emily ran her finger along the numbers, counting in her head.
“Thirteen numbers, same as the phone number on the clue,” she said.
James flipped over his other book. Its ISBN also began with 978 and had thirteen digits. Emily’s collection of Poe works had another thirteen-digit ISBN number. Every book had a similar but unique number. The Gold-Bug had no bar code at all, but that made sense if Mr. Griswold had made it especially for his game.
“Mr. Griswold’s clue leads to another book!” Emily said.
They ran to the computer bank to look up the ISBN number. In the search browser, there was an option for ISBN/ISSN Exact Match. Emily selected that and typed in the thirteen-digit number from the Black Cat flyer. Holding her breath, she clicked the red arrow and watched the computer do its thinking spiral, then slowly load a new page. The Maltese Falcon by Dashiell Hammett.
“No way,” Emily said.
“That must be it!” James said. “But why did the flyer say to call Samuel? Are we supposed to do that, too, or do you think he just wrote that to make it look like a real lost-cat flyer?”
Emily clicked on the “About the Author” link for the book. “He used ‘Samuel’ because of that.” She tapped the screen. “Dashiell Hammett’s real first name was Samuel. Maybe he thought using Dashiell would be too much of a giveaway.”
As exciting as it was to know she’d figured out another one of Mr. Griswold’s puzzles, and must therefore be that much closer to the end, staring at the cover of The Maltese Falcon felt like starting from scratch again. Now what were they supposed to do with this clue? The satisfaction of accomplishing something could be very fleeting.
“I feel like this book is familiar for some reason. But I don’t think I’ve heard of it until now,” James said.
“It’s set in San Francisco. Maybe you’ve heard of it because it has to do with the city,” Emily said.
“How did you know that?”
“My parents gave it to me as a San Francisco–themed present before we moved here. Or maybe you saw it in my room.”
“Yeah, maybe,” James said. The bell rang, signaling the end of lunch. “Doesn’t matter anyway. What matters now is that soon we deliver Her Royal Fungus with the cipher of doom. What an awesome day, huh?”
* * *
By the end of Mr. Quisling’s class, Emily’s mind had drifted away from the Roman Empire and back to The Maltese Falcon clue. She wrote Dashiell Hammett in her notebook and circled it. Around the author’s name she wrote: Born here? Wrote books here? School? Because the Black Cat clue had led them to a San Francisco location, maybe this clue was meant to lead them to another spot in the city. She’d have to reread her copy of The Maltese Falcon to get more ideas.
“Mr. Quisling?” Next to Emily, James raised his hand. “Class is almost over. Are you going to collect ciphers for the week?”
Their teacher looked up at the clock and capped his dry-erase marker. “So it is. I assume you have one, Mr. Lee?”
“I do,” James said, and flipped to the back of his binder. At the same moment, Maddie stood up.
“I have one, too.” She walked her stack of papers to the front of the class and handed them to Mr. Quisling. She resumed her seat behind James, who was pulling pencils, crumpled papers, and textbooks from his backpack and piling them onto his desk.
“It was right here,” he muttered.
“Excellent, Maddie.” Mr. Quisling held the page forward for the class to see. The sheet of paper had a short paragraph at the top.
Something slithered in Emily’s belly, as if a snake were winding its way around her stomach. All she could picture was their stuff, abandoned at the library table while they’d been at the computer bank discovering Mr. Griswold’s next clue. Leaning across the aisle she whispered to James, “That isn’t…”
“This looks interesting,” Mr. Quisling said. “Your average paragraph about ninja monkeys—or is it?”
James looked up. “Hey, that’s my cipher!”
“No, it’s not.” Maddie hit the perfect note of disbelief and outrage. “That’s mine. I just turned it in.”
James twisted in his seat to argue with her. “I spent all weekend working on that.”
Maddie’s eyebrows bunched together in a frustrated glare. “Funny, because I spent all weekend working on that, too.”
If Emily hadn’t just sat next to James at lunch and listened to him break down his new cipher and explain how it worked, she might be swayed by Maddie’s performance.
Mr. Quisling turned the cipher around to study it. “Maddie’s name is typed on this,” he commented.
“Well, maybe she retyped it after she stole it from me.”
“I didn’t steal anything!”
“Enough!” Mr. Quisling said as the bell rang. The rest of the students shifted in their seats, packing up their backpacks.
“Mr. Quisling!” Emily raised her voice over the sliding desks and chatter that filled the hallway outside their room. “That’s James’s cipher. He showed it to me at lunch.”
Maddie blinked her eyes rapidly, like she was fighting back tears. “Of course she is going to back him up.”
“I said enough! It’s clear something is amiss here, but there’s no time to get to the bottom of this. You know how I feel about cheating.” Mr. Quisling ripped the paper in two. He picked up the stack of copies Maddie had turned in and dumped them and the torn pieces into his recycling bin. “That cipher is invalid.” He pointed a finger between James and Maddie. “For this week only, I will allow you to submit a different cipher. But if there is even the slightest suggestion that one of you has cheated, you’ll be disqualified from the challenge completely.”
Emily warily watched James shove his belongings back into his backpack. He didn’t talk as they left Room 40. They walked silently past slamming lockers and laughing students.
“How did Maddie type her name on your paper, anyway?” Emily finally asked.
James shrugged. “It was a short paragraph. It wouldn’t have taken her long to retype it and make copies.”
“But why?” Emily said, incredulous.
“Maddie doesn’t like to lose,” James said glumly.
“But she had to know she couldn’t win a homework pass with your cipher.”
“She didn’t want to win a homework pass. She wanted to make sure I didn’t, and she wanted to rub it in at the same time,” James muttered.
“So she’s threatened by you,” Emily said, trying to shine a light on a bright side. “And she should be. You could still use your bacon-and-eggs cipher. Just submit a different encrypted message tomorrow.”
She had hoped for a smile with the “bacon-and-eggs,” but James didn’t look up from the linoleum.
“Maddie stole the cipher key, too. Once you know how a cipher works, it’s easy to break.” He stopped abruptly in a hallway intersection. With his hands shoved in his hoodie pocket and eyes still on the floor, he muttered, “I forgot I have to do something,” before turning away and getting swallowed by the crowd.