The Unbreakable Code

by Jennifer Chambliss Bertman

  There was a clatter at the front of the store. Hollister yelped. Emily and James ran through the aisles and found the store owner holding a dolly stacked with cardboard boxes. The top box had fallen off, spilling the hardback books contained inside.

  “Are you okay, Hollister?” Emily asked.

  “Fine, I’m fine,” Hollister said. He shook his head and squeezed around the dolly to start picking up the dropped books. Emily and James stooped down to help him.

  “Just clumsy, I guess,” Hollister said. “I swear this table’s been moved over a few inches. I clipped it when I was rolling these boxes.”

  Charlie was at the front counter writing something down. Emily was pretty sure he must have moved the table when he was taking his photos earlier, so she wondered if he’d say anything or apologize, but he didn’t. Maybe he hadn’t heard Hollister. Perhaps because she’d been staring at him so long, or maybe because his guilt prompted him, Charlie looked up.

  “Need any help?” he asked.

  “Nah, I’ve got it,” Hollister said.

  The cardboard box that spilled had been filled with copies of the same book. There was an illustration of the San Francisco skyline on the cover. Emily picked one up and flipped through the pages. “This is a cool book,” she said.

  “Isn’t it? It’s brand-new—we just got them in. It’s about the changing landscape of San Francisco over the years, but the book itself is truly a work of art. Go on. Look through it. I can clean up my own mess.”

  Emily and James carried the book to the front counter to get out of Hollister’s way. They flipped to the first page, which had an illustration of a barely recognizable San Francisco with undeveloped hills and only a few low buildings close to the water.

  “Look, that inlet is probably Yerba Buena Cove,” Emily said, thinking of their talk with the docent at the Maritime Museum. As they turned the pages in the book, detailed cutouts layered on top of the previous page so gradually the city developed and aged right before their eyes.

  “It reminds me of a grille cipher,” James said. “I would have never thought of using it with illustrations, though.”

  “What’s a grille cipher?” Hollister asked as he stacked the scattered books back into the cardboard box.

  “It’s a way to conceal a message. I always thought of it for words hidden in a paragraph, but I suppose it could be a drawing, too. With words, you would take a secret message like attack at midnight and write out something that sounds boring but uses those words. Like Gary the attack rooster was at it again, practicing his ninja skills at midnight. The person who is decoding the message has the grille—it’s like a piece of cardboard with holes cut in it. When you put the grille over the paper with the story about Gary the rooster, everything gets covered up except the message attack at midnight.”

  “Fascinating,” Hollister said. “What an interesting way to hide something in plain sight.”

  Before heading home, Emily and James put the copies of Tom Sawyer back where they’d found them, including re-hiding the one for Book Scavenger. Even if Mr. Quisling wasn’t going to look for it, maybe another Book Scavenger user would.

  Walking home, Emily felt a little down about how much further along Mr. Quisling probably was toward figuring out the unbreakable code until she realized that Coolbrith had posted her breakup message after Mr. Quisling asked about meeting up. Which meant they probably never talked about the map, which meant Mr. Quisling might know only as much as Emily and James did: that a map existed.

  The thought made her feel lighter. It also made her realize that if she wanted to get information about the map from someone, Coolbrith might be a better choice than Mr. Quisling.

  And Emily had an idea for exactly how she could do that.

  * * *

  “Should I be worried about you doing this?” James asked. “I feel like I should be worried.”

  They were back in his room. He was sprawled on his floor with computer paper and scissors, testing out some grille cipher creations while Emily sat at the computer.

  “No, you shouldn’t be,” she said.

  Coolbrith didn’t have private messaging enabled in Book Scavenger, so Emily had done an Internet search, hoping that the unusual name Miranda Oleanda would turn up some results. And she’d had good luck, because there, in the middle of a list of results that mostly had to do with the flower oleander, was a profile on a scrapbooking forum. The woman in the photo looked like she could be an older version of the teenager who had been buddy-buddy with Mr. Quisling at the Niantic dig many years ago, and there was an e-mail address in the profile, too.

  Emily quickly typed out a message:

  Dear Ms. Oleanda,

  Our teacher is Mr. Quisling. We play Book Scavenger with him, which he tells us you like, too. Recently, he told us about the unbreakable code and how you are working on it with him. He showed us the map once, and we thought it would make an awesome gift to copy the map and frame it for him as a surprise. But we don’t know where to find it. Could you tell us? Remember, this is a surprise.

  Thank you,

  Mr. Quisling’s students

  “You can’t send that!” James cried. He’d left his paper cuttings and scissors on the floor to see what Emily was up to.

  “Why not?” Emily asked.

  “Because … because … are you kidding me? For starters, we don’t know this lady. Second, what if she talks to Mr. Quisling?”

  “That’s why I kept it anonymous. My e-mail has a generic handle. She won’t know it’s me. All she can tell him is that some of his students like him enough to want to give him a gift—that’s not so awful.”

  “And he’ll know that whoever sent this e-mail is lying because he never told us about the unbreakable code. He’ll know someone else is trying to solve it.”

  “Technically, he did tell us when he dropped that note at Hollister’s party. And anyone can look at the unbreakable code in the library. It’s not like it’s top-secret information. Anyway, she probably won’t even reply. Worst-case scenario is we hear nothing, but maybe this will give us the clue we need.”

  Emily pressed Send. James covered his face with his hands. “I can’t believe you did that!” He peeked through his fingers.

  Emily giggled. This revelation about the existence of a map had turned her into a giant, grinning balloon. Imagine being the person who proved that something that was considered impossible was actually possible?

  CHAPTER

  20

  THE NEXT DAY Mr. Quisling stood in the dimly lit classroom, illuminated by the projector as he described slides about ancient Greece. Emily drew a palm tree on the margin of her notebook, glancing up every now and then, and jotting something down in her class notes. Next to her, James was using a sharp pencil to poke holes in a piece of binder paper in order to make a grille cipher. He poked a final hole in the paper and placed it on top of his notebook. Smiling at the results, he lifted the notebook up for Emily to see:

  Emily smiled, then quickly redirected her attention to Mr. Quisling so he wouldn’t notice they hadn’t been listening to him talk about King Minos. She wrote down the next few things he said, then while his voice droned on, she outlined bubble letters across the top of her page.

  Change of heart.

  She filled in each letter with diagonal stripes and thought about the week before, when Mr. Quisling had been preoccupied solving the Book Scavenger code in class, and then they followed him to the redwood park. Now she realized they’d watched their teacher decipher a breakup message. Mr. Quisling was probably heartbroken.

  Their teacher rubbed the dry eraser against the board, and it flipped out of his hand, bouncing off his chest. Mr. Quisling picked up the eraser and kept talking, brushing at the blue ink mark on the fabric. It was the same new shirt James had complimented him on last week, the day they followed him. He had probably worn it that day in hopes that he might see Miranda.

  Emily sighed. She wouldn’t have thought it was possible, but sh
e felt sorry for Mr. Quisling.

  * * *

  Emily and James were in her room, hunched over their tracing of the unbreakable code. That was how they’d spent the majority of their free time that week, staring at the page as if they could summon the letters through the powers of eyesight to reveal their secrets and tell them where the dang map was already.

  “We could ask Mr. Quisling,” James said.

  “You’ve said that before, but now we’re in an even worse spot,” Emily said. “Um, Mr. Quisling? Not only did we decipher your secret message from the book party, but we followed you and decoded the messages you traded with your ex-girlfriend, and now we know about the unbreakable code and that a map exists somewhere, and could you tell us more about this map?”

  “Don’t forget to mention you e-mailed his ex-girlfriend, too,” James said. “He’ll be sure to help us then.”

  Emily squirmed uncomfortably. “Oh, yeah. I did that, didn’t I?” It had been several days since she sent the e-mail, and there had been no response.

  “Okay, let’s think like a gold miner.” James stood up and stretched, shaking his hands, then arms and legs like he was getting ready to run a race. “I’m a grizzled old miner, and I’ve hidden some gold. I want to make sure I can find it again, so I write directions in a secret code and make a map. Where would I put the map?”

  “It seems weird to have two different objects to keep track of,” Emily said. “Like, what if the map got lost? Or the message? Why wouldn’t you try to limit yourself to one piece of paper?”

  “It’s more secure if you double up,” James pointed out. “If you need both the map and the cipher to figure out where the gold is, it makes it harder for someone else to solve. Think of it like this.”

  James flipped to a clean page in Emily’s notebook and wrote the following key:

  A

  B

  C

  D

  E

  F

  G

  H

  I

  J

  K

  L

  M

  B

  C

  D

  E

  F

  G

  H

  I

  J

  K

  L

  M

  N

  N

  O

  P

  Q

  R

  S

  T

  U

  V

  W

  X

  Y

  Z

  O

  P

  Q

  R

  S

  T

  U

  V

  W

  X

  Y

  Z

  A

  “This is a simple substitution cipher, right?” James wrote down a series of letters and handed the notebook back to Emily. “Now solve this message.”

  SPDLFU DBU DPNF GMZ BXBZ

  It only took her a couple of minutes. “Rocket cat come fly away,” she said.

  “Right! But then what if you combined that substitution cipher with a rail fence cipher?”

  In a rail fence cipher, you wrote the letters of your message up and down in a zigzag, so on the notebook page, James used the already encrypted message and wrote:

  S D F D U P F M B B

  P L U B D N G Z X Z

  After that, he grouped the letters into sets of five, which was the final step with a rail fence cipher:

  SDFDU PFMBB PLUBD NGZXZ

  “Doubling up your security tactics makes it more difficult to solve,” James said. “Even if someone figured out the substitution cipher, they would end up with RCECT OELAA OKTAC MFYWY, and they probably wouldn’t realize they’d deciphered the letters correctly because they’re in a jumbled order.”

  “I know you’re right, but if I was trying to remember where I left something valuable, I wouldn’t want to keep track of two objects necessary for finding my way back. What if I lost one of them?”

  Emily studied the tracing from the library, flipping the page over to see the doodles they had copied, and then back to the letters. Smoothing the paper, she noticed the doodles—four circles and some squiggle lines—showed through, faintly. She flipped the page over again.

  The drawings looked like something she would do mindlessly in class, or like what her mom did when she was on the phone. But what if they weren’t as mindless as they looked?

  Emily folded the notebook paper in half.

  “You’re not giving up on it, are you?” James asked.

  “No, I’m experimenting.” She held up the page so the light shone through. The doodles and letters overlapped. Most of it was a muddle of lines and curves, except for one circle where an x landed perfectly in the center.

  “Check that out,” Emily said. She opened the paper and scanned the grid of letters. In all the letters, there was only one x. She folded the paper again, pressing a hand across the crease to make it flat and smooth. It wasn’t a fluke—the x was the only letter that fell inside a circle.

  “X marks the spot,” Emily said. “The unbreakable code is the map.”

  “You might be right,” James said, leaning close to the paper. “It’s still doubling up on the security, but the miner wouldn’t have needed to worry about keeping track of two papers, like you said. So what does the circle represent?”

  “Maybe you find out when you decode the cipher,” Emily said.

  “Or…” James slid the paper away and turned the drawing to the side. “What if the squiggly lines mean water? Like the San Francisco Bay? And the circles are islands? These three are grouped together like Angel Island, Alcatraz, and Treasure Island. And the x marks the spot on…”

  “Treasure Island,” Emily said. “The treasure might really be there! Have you been before?”

  James shook his head. “Not yet. But I think we need to make a trip.”

  CHAPTER

  21

  EMILY THOUGHT there might be a ferry they could take to Treasure Island, but it turned out you had to drive there, even though it was an island. To drive, they needed grown-ups, and James’s mom and grandmother had a big event they were preparing food for. Emily’s parents, however, were always up for exploring new places. When Emily pitched the idea of a bike ride around Treasure Island, they immediately agreed. The only problem was her parents refused to drive during rush-hour traffic, which was the only option if they went after school, so it wasn’t until Saturday that the Cranes and James piled into Sal, the Cranes’ old minivan.

  They drove halfway across the Bay Bridge, where they exited into the tunnel that bored through the rugged and craggy landmass in the middle of the bay. The van curved out of the tunnel like a gumball dispensed from a machine. The road sloped around the green-clad island and then straightened out and became flatter than flat along a waterfront sparsely lined with palm trees.

  As she took in the paved road and sidewalks, the Treasure Island Yacht Club, and an old horseshoe-shaped building, Emily realized how impossible this mission might be. What if the gold was on the island, but a building had been erected over its burial spot? They’d never find it.

  Well, they were here. It couldn’t hurt to scope the place out, she told herself. Emily had learned from both solving puzzles and book hunting that it was always good to keep your mind open to possibilities and to never stop observing. You might find the key to unlock a difficult problem in the most unlikely of spots.

  They parked next to a small marina in front of the horseshoe building, which looked like it had seen better days, now that they were closer. The parking lot was practically empty. Emily wasn’t used to going someplace in San Francisco so unpopulated. They rounded the building to find the bike rental shop tucked in the back. A jackhammer rattled the quiet, and Emily could see a construction site in the distance. It prompted a new worry: Maybe the gold would be found by a construction crew, similar to how the
Niantic was rediscovered.

  “Do you have the coupon?” Emily’s dad asked.

  Her mom dug through her purse, pulling out a printout from a website. “Two-for-one bike rentals!” She waved the paper and added, “We’re covering yours, James. Don’t worry about it.”

  Emily internally cringed with the realization that this outing was costing her parents more money. Even though they didn’t seem worried about it, she knew they must be under the surface. She straightened her shoulders and tightened her ponytail. If it could help her stay in San Francisco, that was all the more reason to find this treasure.

  Once the Cranes and James got set up with bikes and helmets, they pedaled to the sidewalk that ran along the water. The view of the San Francisco skyline from here was better than any postcard Emily had seen. But the island itself struck Emily as … dilapidated. Maybe she’d connected the name Treasure Island too closely with the book, which made her imagine something lush and tropical. She certainly hadn’t anticipated the boarded-up buildings and rusted docks they cycled past.

  Her parents slowed to a stop and straddled their bikes, facing the water and the city. Her mom pulled her camera from the bag slung across her body and began snapping photos. A rocky border separated the sidewalk from the water. Just beyond her brother’s foot, Emily could see a watermelon-sized rock with the words I got mugged in blue spray paint.

  “This is not what I was expecting,” Emily said, adjusting the chinstrap of her bike helmet.

  “With a view like this, you’d think Treasure Island would be the most desirable place to live, wouldn’t you?” her mom said, twisting her focal lens.

  “I read it was owned by the navy until recently,” Emily’s dad said.

  “Is that so?” her mom replied. Click. Click. “Is that why the island was originally built? For the navy?”

  Emily squinted at her mom, not sure she heard her right. “What do you mean, ‘built’?”

  Her mom lowered the camera. “This isn’t natural. Can’t you tell? See how flat everything is?”