Fourteen-year-old Johnny is a silversmith’s apprentice in Boston. Though he’s clever and well-liked, he’s cruel to his fellow apprentices, Dove and Dusty. He has a good, if somewhat antagonistic relationship with Cilla, his master Mr. Lapham’s granddaughter—the two are going to marry once Johnny finishes his apprenticeship. One night, while Johnny and Cilla are on the wharf with Isannah, the youngest Lapham sister, Johnny shares that he has a middle name—Lyte—and is a member of the influential Lyte family. He later shows Isannah his silver cup with the Lyte crest on it, which his deceased mother gave him and told him to keep secret unless he needs help from the Lytes.
Wealthy John Hancock approaches Mr. Lapham about creating an intricate sugar basin. Mr. Lapham charges Johnny with sculpting the handles. Johnny has to ask the esteemed silversmith Paul Revere for help, but he finally gets the handles right. However, after Mr. Lapham overhears Johnny being particularly mean to Dove, he forbids Johnny from working, meaning the basin won’t be finished on time. Mrs. Lapham, Mr. Lapham’s daughter-in-law, encourages Johnny to work on Sunday to finish—but Dove gives Johnny a cracked crucible, resulting in the molten silver spilling and Johnny burning his hand. Johnny’s hand heals, but the injury leaves his thumb fused to his palm: he won’t work silver again.
Enraged and feeling purposeless, Johnny begins going out to find work. However, he refuses to do unskilled work, and he can no longer perform skilled work. Johnny grows increasingly depressed, though no less arrogant. The one good thing that happens to Johnny is that he meets an older boy named Rab, who works as a printer’s apprentice at the Boston Observer. After spending a night sleeping on his mother’s grave, Johnny approaches Merchant Lyte for help. Johnny takes his cup to Merchant Lyte and tells his story—but Merchant Lyte accuses him of stealing the cup and has Johnny imprisoned. Rab gets Johnny legal representation and procures Cilla and Isannah to speak as witnesses, and Johnny wins his case. However, when Johnny goes to Merchant Lyte and tries to sell him the cup, Merchant Lyte steals it.
Johnny returns to the Boston Observer’s office, where Rab and Uncle Lorne, the printer, agree to hire Johnny to deliver papers. Rab teaches Johnny to ride Goblin, a striking but flighty horse. Soon, Johnny is a skilled horseman. He spends several days per week riding and the other half reading in the Lornes’ extensive library. Though he occasionally meets Cilla and Isannah at the local well, he goes out of his way to forget his old life—especially since Mrs. Lapham has now brought on an unlikeable man named Mr. Tweedie to be Mr. Lapham’s business partner.
It's now the fall of 1773, and New England is in an uproar over the British attempt to pass off taxes on tea onto the colonists, who have no representation in the British Parliament. Johnny now works as a spy for the secret rebel group the Boston Observers. He agrees to participate in the planned protest: a bunch of apprentices are going to throw the tea into the harbor on December 16 if the ships can’t return to England. The day comes, and the ships won’t be allowed to return to England. So, Johnny, Rab, and hundreds of apprentices board the ships and throw the tea into the harbor.
In retaliation, England closes Boston’s harbor the following spring, decimating Boston’s economy. The Boston Observer gets smaller, but Uncle Lorne refuses to stop printing. With so little to do, Johnny and Rab spend most of their time watching the British soldiers drill. As Rab has begun drilling with the Minute Men in Lexington, he desperately wants a proper musket. Johnny also begins carrying mail for British officers (which allows him to spy on them) and reconnects with Cilla. He learns that Miss Lavinia Lyte took an interest in beautiful Isannah and has now taken in both girls as servants (though Isannah is more of a doll than a servant). Dove comes back into Johnny’s life as well, as Mr. Tweedie fired him and he’s now Colonel Smith’s horse boy. Though Johnny still doesn’t like Dove, he feels bad that the English boys pick on him—and Rab notes that Dove, as an employee of a British officer, might someday pass on useful information.
When Johnny visits Cilla one Thursday, he gets a good look at how the Lapham girls are faring in the Lytes’ household. The Lytes treat Cilla like an unintelligent servant, while Isannah (who now goes by “Izzy”) is attention-seeking and acts immorally. From Mrs. Bessie, the Lytes’ cook, Johnny learns that the Lytes will be going to their country home—but Whigs plan to mob them. A month after the Lytes leave, Johnny sees them return to Boston. Mr. Lyte is gravely ill, and loyal Cilla insists she must return to the country house to retrieve some silver. Johnny offers to drive her there. At the estate, Johnny looks through Merchant Lyte’s papers, pockets some letters for the Observers, and discovers where he thinks he belongs on the Lyte family tree. However, he burns the family tree, for he now realizes his lineage doesn’t matter. Later that summer, Cilla and Johnny admit they have crushes on each other.
By the fall of 1774, most of the Observers have left town to avoid being arrested by the British, but Johnny summons the remaining members for a final meeting. James Otis, who was once the group’s leader but is now seen as mentally unstable, invites himself and gives a rousing speech about what the Whigs are fighting for: the freedom of all men, everywhere, to “stand up” and live with dignity. Johnny finds it very moving. Following this, Paul Revere starts a spy network of artisans. It’s Johnny’s job to spy on Colonel Smith, and Johnny successfully uncovers a British plot to seize rebel military stores.
The British are getting antsy: while Johnny can usually ride Goblin on the Common without issue, one day, the British accost him. Johnny escapes by encouraging Goblin to bolt; Goblin races through Boston without a bridle and stops finally in the Lytes’ stable yard. There, a British soldier named Pumpkin tells Johnny that many British soldiers will happily read the copies of the Boston Observer that Johnny dropped during the altercation; many believe in the rebels’ cause—including him. Indeed, he’d like to be a farmer and desert. Johnny helps Pumpkin put together a disguise and leave Boston in exchange for his musket, which Johnny gives to Rab. However, a few weeks later, Johnny witnesses Pumpkin shot for deserting.
In the middle of April 1775, the British soldiers begin acting oddly. Johnny runs around town for Dr. Warren and Paul Revere, gathering intel. Rab insists on leaving town—war is coming and soon, the British will close the gates, and Minute Men won’t be able to get out. The following day, Johnny helps Dove polish Colonel Smith’s campaign saddle and discovers that Smith is going to lead a regiment of British soldiers across the river and then to either Lexington or Concord. Johnny immediately reports back to Dr. Warren and Paul Revere. The men activate their notification system: Paul Revere will paddle across the river and then ride to notify Minute Men, while Billy Dawes will walk out of Boston and do the same.
The following morning, Johnny wakes up in Dr. Warren’s surgery and learns that shots were fired at Lexington—the British won handily and then headed for Concord. Dr. Warren leaves to attend to the wounded, telling Johnny to stick around, gather more info, and then find him later. Johnny watches the British forces move out to support Colonel Smith’s regiment. Knowing he needs to get across the river himself, Johnny goes to Mrs. Bessie and Cilla, who still have Pumpkin’s uniform—Johnny can use it to sneak across the river. But while he’s there, Miss Lavinia tells Johnny that he truly is a Lyte. His mother was the rightful owner of the cup, and after the war, Johnny will be able to put in claims for property. But now, she and Izzy are going to England, where Izzy will train as an actress.
Johnny has no time to think about this new information. Instead, he puts on Pumpkin’s uniform, gets it dirty, and arrives around nightfall at the river, where wounded British soldiers are coming back to Boston. He sees many of his friends, but he stops himself from trying to help them—they’re his enemies now. After sneaking across the river, Johnny goes from tavern to tavern and town to town, trying to track down Dr. Warren and news of Rab, who would’ve fought at Lexington. Finally, Johnny meets Dr. Warren in Lexington. Rab is seriously injured, but he gives Johnny his musket. Soon after sending Johnny away, Rab dies.
Seeing how distraught Johnny is, Dr. Warren asks to see Johnny’s burnt hand. He says that Johnny’s thumb is only held to his palm with scar tissue. Dr. Warren offers to cut the scar tissue, which would enable Johnny to hold a musket and join the Minute Men. Thrilled and hopeful, Johnny thinks of Rab. Though Rab and other brave men like him have died and will continue to die, what they believe in never will.
