The main character and narrator is 17-year-old David Balfour[a]. His parents have recently died, and he is out to make his way in the world. He is given a letter by a family friend, a minister of Essendean named Mr. Campbell, to be delivered to his family's ancestral estate, the House of Shaws in Cramond. David hopes that the letter will allow him to obtain financial assistance from his only living relative - his uncle Ebenezer.
David arrives at the ominous House of Shaws and is confronted by the paranoid Ebenezer with a loaded blunderbuss. His uncle is also miserly, living on "parritch" and small ale, and the House of Shaws itself is partially unfinished and somewhat ruinous. David is allowed to stay and soon discovers evidence that his father may have been older than his uncle, thus making David the rightful heir to the estate. Ebenezer asks David to get a chest from the top of a tower in the house but refuses to provide a lamp or candle. David is forced to scale the stairs in the dark and realises that not only is the tower unfinished in some places, but the steps simply end abruptly and fall into an abyss. David concludes that his uncle intended for him to have an "accident", perhaps so as not to have to give over his nephew's inheritance.
David confronts his uncle, who promises to address the matter the next morning. A ship's cabin boy, Ransome, arrives the next morning and tells Ebenezer that Captain Hoseason of the brig Covenant needs to meet him to discuss business. Ebenezer takes David to a pier on the Firth of Forth, where Hoseason awaits, and David makes the mistake of leaving his uncle alone with the captain while he visits the shore with Ransome. Hoseason later offers to take them on board the brig for a drink and a brief tour, and David complies, only to see his uncle returning to shore alone in a skiff. David is then immediately struck senseless.
David awakens, bound hand and foot, in the hold of the ship, and learns that per arrangement with David's uncle, the captain plans to sell him into slavery in the Carolinas. But the ship encounters contrary winds, which drive her back toward Scotland. Fog-bound near the Hebrides, they strike a small boat. All of the small boat's crew are killed except one man, Alan Breck Stewart, who is brought on board and offers Hoseason a large sum of money to drop him off on the mainland. David later overhears the crew plotting to kill Alan instead. David and Alan barricade themselves in the roundhouse, where Alan kills the murderous helmsman and David wounds Hoseason. Alan then demonstrates his superior fighting skills as he easily kills five more men and intimidates the remaining crew into backing down.
Hoseason has no choice but to give Alan and David passage back to the mainland. David tells his tale to Alan, who in turn states that his birthplace, Appin, is under the tyrannical administration of Colin Roy of Glenure, the King's factor and a Campbell. Alan, who is a Jacobite agent and wears a French uniform, vows that should he find the "Red Fox" he will kill him.
The Covenant tries to negotiate a difficult channel without a proper chart or pilot and is soon driven aground on the notorious Torran Rocks. David and Alan are separated in the confusion, with David being washed ashore on the isle of Erraid, near Mull, while Alan and the surviving crew row to safety on that same island. David spends a few days alone in the wild before getting his bearings.
David learns that his new friend has survived, and David has two encounters with beggarly guides: one who attempts to stab him with a knife, and another who is blind but an excellent shot with a pistol. David soon reaches Torosay, where he is ferried across the river, receives further instructions from Alan's friend Neil Roy McRob, and later meets a catechist who takes the lad to the mainland.
Kidnapped sketch of route of ship and David's walk across ScotlandAs he continues his journey, David encounters none other than the Red Fox, Colin Roy Campbell himself, who is accompanied by a lawyer, a servant, and a sheriff's officer. When David stops the Campbell man to ask him for directions, a hidden sniper kills the King's hated agent.
David is denounced as a conspirator and flees for his life, but by chance reunites with Alan. The youth believes Alan is the assassin, but Alan denies responsibility. Alan and David then begin their flight through the heather, hiding from government soldiers by day. As the trek drains David's strength, his health rapidly deteriorates; by the time they are set upon by wild Highlanders who are sentries for Cluny Macpherson, an outlawed chief in hiding, the lad is barely conscious. Alan convinces Cluny to give them shelter, and David is tended by a Highland doctor. He soon recovers, though in the meantime Alan loses all of their money at cards with Cluny, only for Cluny to give it back when David practically begs for it.
When David and Alan resume their flight in cold and rainy weather, David becomes ill again, and Alan carries him on his back down the burn to reach the nearest house, fortuitously that of a Maclaren, Duncan Dhu, who is both an ally of the Stewarts and a skilled piper. David is bedridden and given a doctor's care, while Alan hides nearby, visiting after dark.
In one of the most humorous passages in the book, Alan convinces an innkeeper's daughter from Limekilns (unnamed in Kidnapped but called "Alison Hastie" in its sequel) that David is a dying young Jacobite nobleman, despite David's objections, and she ferries them across the Firth of Forth. There, they meet a lawyer of David's uncle's, Mr. Rankeillor, who agrees to help David properly claim his inheritance. Rankeillor explains that David's father and uncle had once quarrelled over a woman, David's mother, and the older Balfour had married her, informally giving the estate to his brother to settle their dispute while living as an impoverished schoolteacher with his wife. This agreement had lapsed with his death.
David and the lawyer hide in bushes outside Ebenezer's house while Alan speaks to him, claiming to be a man who found David nearly dead after the wreck of the Covenant and says he is representing folk holding him captive in the Hebrides. He asks David's uncle whether Alan should kill David or keep him. The uncle flatly denies Alan's statement that David had been kidnapped but eventually admits that he paid Hoseason "twenty pound" to take David to "Caroliny". David and Rankeillor then emerge from their hiding places, and speak with Ebenezer in the kitchen, eventually agreeing that David will be provided two-thirds of the estate's income for as long as his uncle lives.
The novel ends with David and Alan parting ways on Corstorphine Hill; Alan returns to France, and David goes to a local bank to receive his money.
