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The Blackthorn Key



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Following a series of murders, an apothecary’s apprentice must solve puzzles and decipher codes in pursuit of a secret that could destroy the world in this suspenseful debut novel.

“Tell no one what I’ve given you.”

Until he got that cryptic warning, Christopher Rowe was happy, learning how to solve complex codes and puzzles and creating powerful medicines, potions, and weapons as an apprentice to Master Benedict Blackthorn—with maybe an explosion or two along the way.

But when a mysterious cult begins to prey on London’s apothecaries, the trail of murders grows closer and closer to Blackthorn’s shop. With time running out, Christopher must use every skill he’s learned to discover the key to a terrible secret with the power to tear the world apart.

In his stunning debut novel, Kevin Sands brings readers on a heart-stopping adventure rich with suspense, mystery, and unforgettable characters.


The Blackthorn Key CHAPTER 1

Tom wasn’t listening. He was deep in concentration, tongue pinched between his teeth, as he steeled himself for combat with the stuffed black bear that ruled the front corner of my master’s shop. Tom stripped off his linen shirt and flung it heroically across the antimony cups gleaming on the display table near the fire. From the oak shelf nearest to him, he snatched the glazed lid of an apothecary jar—Blackthorn’s Wart-Be-Gone, according to the scrawl on the label—and held it on guard, a miniature ceramic shield. In his right hand, the rolling pin wobbled threateningly.

Tom Bailey, son of William the Baker, was the finest fake soldier I’d ever seen. Though only two months older than me, he was already a foot taller, and built like a blacksmith, albeit a slightly pudgy one, due to a steady pilfering of his father’s pies. And in the safety of my master’s shop, away from the horrors of battle like death, pain, or even a mild scolding, Tom’s courage held no equal.

He glared at the inanimate bear. The floorboards creaked as he stepped within range of its wickedly curved claws. Tom shoved the curio cabinet aside, making the brass balances jingle. Then he hoisted his flour-dusted club in salute. The frozen beast roared back silently, inch-long teeth promising death. Or several minutes of tedious polishing, at least.

I sat on the counter at the back, legs dangling, and clicked leather heels against the carved cedar. I could be patient. You had to be, sometimes, with Tom, whose mind worked as it pleased.

“Think you can steal my sheep, Mr. Bear?” he said. “I’ll give you no quarter this day.” Suddenly, he stopped, rolling pin held outward in midlunge. I could almost see the clockwork cranking between his ears. “Wait. What?” He looked back at me, puzzled. “What did you say?”

“Let’s build a cannon,” I said.

“What does that mean?”

“Just what you think it means. You and me. Build a cannon. You know.” I spread my hands. “Boom?”

Tom frowned. “We can’t do that.”

“Why not?”

“Because people can’t just build cannons, Christopher.” He said it like he was explaining why you shouldn’t eat fire to a small, dull child.

“But that’s where cannons come from,” I said. “People build them. You think God sends cannons down from heaven for Lent?”

“You know what I mean.”

I folded my arms. “I don’t understand why you’re not more excited about this.”

“Maybe that’s because you’re never the one on the pointy end of your schemes.”

“What schemes? I don’t have any schemes.”

“I spent all night throwing up that ‘strength potion’ you invented,” he said.

He did look a little dark under the eyes today. “Ah. Yes. Sorry.” I winced. “I think I put in too much black snail. It needed less snail.”

“What it needed was less Tom.”

“Don’t be such a baby,” I said. “Vomiting is good for you, anyway. It balances the humors.”

“I like my humors the way they are,” he said.

“But I have a recipe this time.” I grabbed the parchment I’d leaned against the coin scales on the countertop and waved it at him. “A real one. From Master Benedict.”

“How can a cannon have a recipe?”

“Not the whole cannon. Just the gunpowder.”

Tom got very still. He scanned the jars around him, as if among the hundreds of potions, herbs, and powders that ringed the shop was a remedy that would somehow get him out of this. “That’s illegal.”

“Knowing a recipe isn’t illegal,” I said.

“Making it is.”

That was true. Only masters, and only those with a royal charter, were allowed to mix gunpowder. I was a long way from either.

“And Lord Ashcombe is on the streets today,” Tom said.

Now that made me pause. “You saw him?”

Tom nodded. “On Cheapside, after church. He had two of the King’s Men with him.”

“What’d he look like?”


“Mean” was exactly what I’d imagined. Lord Richard Ashcombe, Baron of Chillingham, was King Charles’s loyal general, and His Majesty’s Warden here in London. He was in the city hunting for a pack of killers. In the past four months, five men had been butchered in their homes. Each of them had been tied up, tortured, then slit open at the stomach and left to bleed to death.

Three of the victims had been apothecaries, a fact that had me seeing assassins in the shadows every night. No one was sure what the killers wanted, but sending in Lord Ashcombe meant the king was serious about stopping them. Lord Ashcombe had a reputation for getting rid of men hostile to the Crown—usually by sticking their heads on pikes in the public square.

Still, we didn’t need to be that cautious. “Lord Ashcombe’s not coming here,” I said, as much to myself as to Tom. “We haven’t killed anyone. And the King’s Warden isn’t likely to stop by for a suppository, is he?”

“What about your master?” Tom said.

“He doesn’t need a suppository.”

Tom made a face. “I mean, isn’t he coming back? It’s getting close to dinnertime.” He said “dinnertime” with a certain wistfulness.

“Master Benedict just bought the new edition of Culpeper’s herbal,” I said. “He’s at the coffeehouse with Hugh. They’ll be gone for ages.”

Tom pressed his ceramic shield to his chest. “This is a bad idea.”

I hopped down from the counter and grinned.

• • •

To be an apothecary, you must understand this: The recipe is everything.

It isn’t like baking a cake. The potions, creams, jellies, and powders Master Benedict made—with my help—required an incredibly delicate touch. A spoonful too little niter, a pinch too much aniseed, and your brilliant new remedy for dropsy would congeal instead into worthless green goo.

But new recipes didn’t fall from the sky. You had to discover them. This took weeks, months, even years of hard work. It cost a fortune, too: ingredients, apparatus, coal to stoke the fire, ice to chill the bath. Most of all, it was dangerous. Blazing fires. Molten metals. Elixirs that smelled sweet but ate away your insides. Tinctures that looked as harmless as water but threw off deadly, invisible fumes. With each new experiment, you gambled with your life. So a working formula was better than gold.

If you could read it.



Tom scratched his cheek. “I thought there’d be more words and things.”

“It’s in code,” I said.

He sighed. “Why is it always in code?”

“Because other apothecaries will do anything to steal your secrets. When I have my own shop,” I said proudly, “I’m putting everything in code. No one’s going to swipe my recipes.”

“No one will want your recipes. Except poisoners, I suppose.”

“I said I was sorry.”

“Maybe this is in code,” Tom said, “because Master Benedict doesn’t want anyone to read it. And by ‘anyone,’ I mean you.”

“He teaches me new ciphers every week.”

“Did he teach you this one?”

“I’m sure he’d planned to.”


“But I figured it out. Look.” I pointed at the notation ?M08?. “It’s a substitution cipher. Every two numbers stand for one letter. This tells you how to swap them. Start with ‘08,’ and replace it with M. Then count forward. So 08 is M, 09 is N, and so on. Like this.”

I showed him the table I’d worked out.















































Tom looked between the cipher and the block of numbers at the top of the page. “So if you replace the numbers with the right letters . . .”

“. . . You get your message.” I flipped the parchment over to show the translation I’d inked on the back.


One part charcoal. One part sulfur. Five parts saltpeter.

Grind separately. Mix.

Which is what we did. We set up on the larger display table, farther from the fireplace, based on Tom’s reasonable suggestion that gunpowder and flames weren’t friends. Tom moved the bleeding spoons from the table and got the mortars and pestles from the window near the bear while I pulled the ingredient jars from the shelves.

I ground the charcoal. Sooty clouds puffed into the air, mixing with the earthy scent of the dried roots and herbs hanging from the rafters. Tom, glancing uneasily at the front door for any sign of my master, took care of the saltpeter, crushing the crystals that looked just like ordinary table salt. The sulfur was already a fine yellow powder, so while Tom swirled the ingredients together, I got a length of brass pipe sealed at one end from the workshop in the back. I used a nail to widen a hole near the sealed end. Into that, I slipped a loop of woven, ash-colored cord.

Tom raised his eyebrows. “Master Benedict keeps cannon fuse?”

“We use it to light things from far away,” I said.

“You know,” Tom said, “things you have to light from far away probably shouldn’t be lit at all.”

The mixture we ended up with looked harmless, just a fine black powder. Tom poured it into the open end while I propped up the pipe. A narrow stream spilled over the side, scattering charcoal grains onto the floor. I stamped the powder in the tube down with cotton wadding.

“What are we going to use for a cannonball?” Tom said.

Master Benedict didn’t keep anything in the store that would fit snugly in the pipe. The best I could come up with was a handful of lead shot we used for shavings to put in our remedies. They scraped down the brass and landed with a hollow thump on the cotton at the bottom.

Now we needed a target, and soon. It had taken a lot longer to put everything together than I thought it would, and though I’d assured Tom that my master wouldn’t return, his comings and goings weren’t exactly predictable.

“We’re not firing this thing outside,” Tom said.

He was right about that. The neighbors would not look kindly on lead shot flying through their parlors. And as tempting a target as the stuffed beaver on the mantel was, Master Benedict was even less likely to appreciate us going to war with the animals that decorated his shop.

“What about that?” I said. Hanging from the ceiling near the fireplace was a small iron cauldron. “We can shoot at the bottom of it.”

Tom pushed aside the antimony cups on the other table, leaving enough space to put down the cauldron. I picked up our cannon and pressed it against my abdomen to hold it steady. Tom tore a scrap of parchment from our deciphered recipe and held it in the fire until it caught. Then he lit the cannon’s wick. Sparks fizzed, racing toward the pipe like a flaming hornet. Tom dived behind the counter and peeked over the top.

“Watch this,” I said.

The blast nearly blew my ears off. I saw a burst of flame, and a mound of smoke, then the pipe kicked back like an angry ox and nailed me right between the legs.

Reading Group Guide

A Reading Group Guide to

The Blackthorn Key

By Kevin Sands


Book Description

In 1665 London, Master Benedict, a kind apothecary, takes Christopher Rowe on as an apprentice, rescuing him from orphanage life. Christopher loves his work of concocting medicines and deciphering codes. But when his safe life is shattered by a string of murders, Christopher must use his new knowledge to track down the dangerous Cult of the Archangel. Except for his friend Tom, it’s hard to tell who’s an ally and who’s an enemy. As Christopher races to uncover secret passages and hidden crypts, and tries to solve urgent puzzles, the future of England is at stake—and so is Christopher’s life.

Prereading Questions           

What does it mean to have a home? What does it mean to “bring aid” to others?

Discussion Questions


1. London provides an exciting backdrop for the story. Find places where the author conveys the sounds, smells, and sights of the city. What words and phrases appeal to the reader’s senses to bring the setting alive?

2. Why is the apothecaries’ motto “I am called throughout the world the bringer of aid”? Describe the work of an apothecary. How is the job related to medicine and science? How is it related to cooking? 

3. A lot of the action takes place in Master Blackthorn’s shop and workshop. Describe the shop, workshop, and tools, pointing to specific passages in the text. How are the shop and workshop similar to places, including businesses, in the modern world?


4. Christopher returns again and again to the importance of home in his life. Discuss why it matters to him and what role his home with Master Benedict plays in the story. How does the idea of home matter at the conclusion of the book? 

5. As the story progresses, we learn that Master Benedict and his friends are pursuing powerful knowledge. What is their ultimate goal? How do they try to reach that goal? Do you consider it a worthy goal?

6. Loyalty and disloyalty are themes explored in terms of relationships, professions, and country. Discuss the main characters, their loyalties, and how they show them. What role does disloyalty play in the plot? Is it always wrong to be disloyal to one’s government?


7. In a short amount of time, Christopher’s courage and ingenuity are tested by a series of unexpected events. Give examples of obstacles he faces and how he deals with them. What do his actions and choices show about his character? Do you admire Christopher?

8. Tom is a tried-and-true friend to Christopher from beginning to end. Describe his personality, his home life, and how he interacts with Christopher. Compare and contrast their characters. Cite scenes in the book where Tom shows his friendship and courage.

9. How does Master Benedict change Christopher’s life? Talk about what you consider the three most important things that he does for Christopher. Describe what kind of person Master Benedict is.

10. Why was Christopher chosen to be an apothecary’s apprentice? Describe his work for Master Benedict, and how Benedict tests him. What character traits make Christopher good at his work?

11. It takes Christopher time to figure out who the real villains are. Describe characters who seem like they might be the wrongdoers and those who really are. What would the story be like without villains?

Plot and Structure

12. Reread “A Warning,” which opens the book and the one page after the first section title. What do they foreshadow about the story? How do they set the tone? Discuss why the author chose to include them before the first chapter.

13. The chapters are divided into large sections. Discuss how those sections are labeled and how each label relates to the chapters that follow. How many days does the main action take? What happens in the “Spring’s End” section? Why does the author structure the chapters this way?

14. While Christopher is trying to uncover the truth of what’s happening, a lot of people are hunting for him. How does Christopher use his skills as an apothecary to evade capture? How does he use them to fight the villains? How do those skills help him find Master Benedict’s secret and understand its purpose?

15. Codes and symbols appear throughout the book. Christopher declares that when he has his own shop, “I’m putting everything in code.” Why does Master Benedict use codes? Give examples where codes and symbols are important in the plot.

16. Christopher’s feelings are hurt in Chapter 8 when Master Benedict hits him, calls him “useless,” and sends him on an errand. What does Christopher realize later about those actions?

Language and Point of View

17. What impact does it have on the reader that Christopher tells his own story? How would the story have been different with a third-person narrator? Discuss the effect on the reader when Christopher asks questions in the text.

18. Similes make actions and objects more vivid through imagery. Analyze the comparisons used in the similes below and others from the book. Which ones draw from the time and place of the story? Which are more general?

like a sack of wheat

like being a prisoner in the Tower dungeon

as if it were Excalibur

recoiled like he’d been shot with a musket

like a thunderclap

twisted like a map of Hell

to speak Latin like Julius Caesar

echoed like a hammer

louder than carriage wheels on cobbles

grew like trees

like a dog herding sheep

keening like a banshee



Tinker, Tailor, Soldier, Sailor

Many jobs besides apothecary appear in The Blackthorn Key. Some are listed below. Have pairs of students research one of the jobs and create a description and poster for it. If the job still exists today, the description should emphasize aspects of it associated with the past such as how books were printed then. Hold an Old-Time Job Fair where students display their posters and answer questions about the job.
















Rag-and-bone man




Secret Messages

Have students write two sentences about the book, one that describes it briefly and one with their opinion of it. Have them use the code from The Blackthorn Key to turn their two sentences into a secret message. They can then trade coded messages with a fellow student and each decode the sentences, checking their answers against the originals. For a more advanced activity, have students try to create their own code, based on the general principle in The Blackthorn Key. For example, use P03 instead of M08, or have the numbers run backward instead of forward. Encourage your students to be creative!

The King and the Puritans

The political situation of the Puritans turns out to be significant to events in the novel. Have students research England in the mid-1600s, especially the 1660s, to better understand the story. Working in pairs or individually, students should use at least one print and one Internet resource to write a short paper that explains the Restoration, Oliver Cromwell, the Puritans, and Oak Apple Day, and briefly addresses how they are part of the plot. As a class, have students share what they have learned.



Guide written by Kathleen Odean, a former school librarian and Chair of the 2002 Newbery Award Committee. She gives professional development workshops on books for young people and is the author of Great Books for Girls and Great Books about Things Kids Love.

This guide has been provided by Simon & Schuster for classroom, library, and reading group use. It may be reproduced in its entirety or excerpted for these purposes.



About The Author

Photograph © Thomas Zitnansky

Since escaping from university with a pair of degrees in theoretical physics, Kevin Sands has worked as a researcher, a business consultant, and a teacher. He lives in Toronto, Canada. He is the author of the award-winning and bestselling Blackthorn Key series.

Product Details

  • Publisher: Aladdin (September 1, 2015)
  • Length: 384 pages
  • ISBN13: 9781481446518
  • Grades: 5 - 9
  • Ages: 10 - 14
  • Lexile ® 630L The Lexile reading levels have been certified by the Lexile developer, MetaMetrics®

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Raves and Reviews

"Captivating! A masterful page-turner brimming with secrets, traps, friendship, intrigue, pigeons, potions, loyalty, and explosions. Kevin Sands has created an engaging, kind-hearted, and humorous young hero in apothecary's apprentice Christopher Rowe. This thrilling adventure will keep you hooked."

– Ingrid Law, Newbery Honor and NYT bestselling author of Savvy

"Magic, adventure, and things that go boom--I love this book."

– Eoin Colfer, author of the bestselling Artemis Fowl series

"First-time novelist Sands has written an exciting and self-assured tale of alchemy and dark secrets . . . Sands adeptly balances the novel’s darker turns with moments of levity and humor, and fills the book with nicely detailed characters and historical background—plus lots of explosions. It’s a story that should have broad appeal, while especially intriguing readers with an existing interest in chemistry, history, and decoding puzzles."

– Publishers Weekly, STARRED REVIEW

"A spectacular debut."

– Kirkus Reviews, STARRED REVIEW

An auspicious debut middle grade novel. Set in the 1600s, the story revolves around Christopher Rowe, the apprentice to a Master Apothecary. After losing his master, Christopher begins to unravel a series of complex codes that his master had, unbeknownst to Chris, been preparing him to solve all along. The more that the protagonist uncovers, the more he finds himself in danger, along with his loyal-to-a-fault best friend. The story is well paced, managing not only to keep readers hooked, but also second guessing everything they think they know. Sands integrates a series of fun and interesting riddles and codes with chemistry concepts—no easy feat. The ending is dynamic and rewarding, with just the right blend of the fantastical and realistic. One of the true triumphs is the author’s ability to create a character who feels accurate for the time period, while also displaying a modern sensibility that will keep readers engaged. The action does get intense, but would still be appropriate for upper elementary school students. VERDICT This is an excellent story for readers who enjoy puzzles, action, and fantasy; keep an eye out for future installments

– School Library Journal STARRED REVIEW

"An auspicious debut middle grade novel . . . The story is well paced, managing not only to keep readers hooked, but also second guessing everything they think they know. Sands integrates a series of fun and interesting riddles and codes with chemistry concepts—no easy feat. The ending is dynamic and rewarding, with just the right blend of the fantastical and realistic. One of the true triumphs is the author’s ability to create a character who feels accurate for the time period, while also displaying a modern sensibility that will keep readers engaged . . . VERDICT This is an excellent story for readers who enjoy puzzles, action, and fantasy; keep an eye out for future installments."

– School Library Journal STARRED REVIEW

"An inspired blend of action, adventure, science, history, and humor, filled with fascinating facts, clever codes, and wonderful characters."

– Stuart Gibbs, bestsellling author of the Spy School series

Awards and Honors

  • ALA Notable Children's Books
  • Keystone to Reading Book Award Reading List (PA)
  • Kansas NEA Reading Circle List Junior Title
  • Oregon Battle of the Books List
  • Louisiana Young Readers' Choice Award Nominee
  • Grand Canyon Reader Award Nominee (AZ)
  • Beehive Award Master List (UT)
  • Maine Student Book Award Reading List
  • Great Stone Face Book Award Nominee (NH)
  • Capital Choices Noteworthy Books for Children's and Teens (DC)
  • Texas Lone Star Reading List
  • Rebecca Caudill Young Readers' Book Award Master List (IL)
  • Dorothy Canfield Fisher Book Award Master List (VT)
  • Edgar Allan Poe Award (Finalist)
  • North Carolina Children's Book Award Nominee
  • Cybils Award
  • Bank Street Best Children's Book of the Year Selection Title
  • MSTA Reading Circle List
  • Tome Society It List
  • Wisconsin State Reading Association's Reading List
  • Manitoba Young Readers' Choice Award Finalist
  • A Best Book for Kids & Teens
  • Heather's Pick - Children
  • Forest of Reading Silver Birch Fiction Finalist
  • Canadian Library Association Book of the Year for Children Finalist
  • Recommended Canadian Reads for Children - Junior Fiction
  • Rocky Mountain Book Award Finalist
  • Canadian Children's Book Centre Violet Downey Book Award Winner
  • Arthur Ellis Best YA Crime Novel Finalist
  • CCBC John Spray Mystery Award Winner
  • Red Cedar Book Award Winner

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