At the beginning of the book, David (Davie) Balfour is a recently orphaned seventeen-year-old. His father has just died, so it is up to him to seek his own fortune. A good friend of his, the Protestant Minister of Essendean, hands Davie a letter from his deceased father telling him to head to the house of Shaws. Davie doesn't know how his father is related to the house of Shaws, but he is excited at the idea of meeting a laird (a kind of Scottish nobleman, like a "lord"). He thinks maybe he'll be able to get a job in the Shaws household. So he walks to the seat of the house of Shaws, near Edinburgh, to ask for help.
When Davie arrives at the house, however, he is much disappointed. The owner is actually Davie's uncle, Ebenezer Balfour. Ebenezer is a miser and kind of a jerk. He even attempts to kill Davie on one occasion. Why is he so threatened by Davie? We're not going to find out for sure until around Chapter 29 of 30. Still, Davie is fairly sure that Ebenezer hates him because he is the rightful heir to the house of Shaws. At any rate, Davie manages to get the upper hand over Ebenezer, who promises to bring Davie to see his lawyer, Mr. Rankeillor, to get a full explanation of Ebenezer's relationship to Davie's father.
On their way to see Mr. Rankeillor, Ebenezer insists on stopping by a ship that he's made some investments in, which is anchored in the seaside town of Queensferry. The ship is called the Covenant and is captained by a Mr. Hoseason. Once Davie is aboard, Hoseason distracts him with a tour of the ship while Ebenezer hops in a rowboat and rows back to shore. Davie has been kidnapped! It turns out that Ebenezer has told Hoseason to sell Davie to a plantation in the Carolinas. Davie's in a real pickle.
The Covenant is still sailing around Scotland when Davie's luck changes. One foggy night, the Covenant accidentally runs into a small boat. There is only one survivor from the boat, a man named Alan Breck Stewart, who is on the run from the law. Alan is carrying a giant money belt, which is too tempting for Captain Hoseason to resist. Hoseason starts to plot with his first mate, Mr. Riach, to steal the gold and kill Alan. Davie overhears this plot and runs to Alan to warn him. Alan and Davie fortify one of the deck rooms, the round-house, and band together against the rest of the Covenant crew. They manage to hold their own, and finally Hoseason agrees to let Alan off in Appin, in the Scottish Highlands, which is Alan's home country. Alan is a Jacobite, meaning that he was part of a Highland uprising against the English throne in 1745. He's a wanted man, and he only feels safe at home in Appin.
Unfortunately, the western portion of the Scottish coast is extremely rocky. The Covenant runs up against a hidden reef and sinks. Davie is thrown from the ship by a wave and winds up washed ashore on the barren island of Earraid. (Here, we definitely suggest that you consider consulting a map.) Davie suffers from hunger and thirst and all-around sickness for a while before discovering that the island he's on is only an island at high tide. When the tide goes out, you can walk to the next island over, the island of Mull, which Davie does.
As Davie starts exploring Mull, he finds out that Alan has been leaving coded messages for him, instructing him on how to find him. Davie heads toward Alan's home of Appin and reaches the forest of Lettermore, where a group of men is making its way down the road. One of the men is Colin Roy Campbell of Glenure (whom Alan calls Red Fox). This man is one of the major enemies of both Alan's clan chief Ardshiel and of the Stewart clan more generally. And just when Davie meets him, Colin Roy is gunned down. Davie sees the murderer and tries to pursue him, only to find that his quick departure has made Davie a suspect in the murder.
In these dire straits, Davie bumps into Alan again. As a known rebel and deserter from the English army (he changed sides during the Battle of Prestonpans in 1754), Alan is also on the run – so they decide to try their luck together. They go on a tough trek through the dry, barren, often cold Scottish Highlands, avoiding capture by both English soldiers and by the Campbell clan. Davie fights off illness, fear, and frustration with Alan on a regular basis.
Finally, after much hardship, the two men reach the start of all of Davie's adventures, Queensferry. Alan wants to go from there to France (where he'll be safe from English soldiers), while Davie is eager to meet Mr. Rankeillor and establish his rights to the estate of the house of Shaws.
Rankeillor, the lawyer, does reassure Davie that he is the rightful heir to the Shaws estate. The trouble is that, in a fight over a woman, brothers Ebenezer and Alexander Balfour (Davie's father) signed an agreement that Ebenezer would get the estate and David would get a wife. This contract is not legally binding, says Rankeillor, but there would still need to be a lawsuit against Ebenezer for Davie to reclaim all of his rights. To avoid such a scandal, Rankeillor suggests blackmailing Ebenezer into giving Davie his money while allowing Ebenezer to continue living in the Shaws house.
The blackmail is achieved in this manner: Alan arrives at the Shaws house and poses as a man working with Captain Hoseason. He says that he has Davie in his care, and he's willing to kill Davie or to keep him a prisoner at Ebenezer's pleasure, as long as Alan gets some money out of it. By using this pose, Alan manages to extort a confession from Ebenezer that he sent Davie with Captain Hoseason to be sold to a plantation in the Carolinas. Once Ebenezer is tricked into admitting this, Mr. Rankeillor appears from a hiding place nearby and tells Ebenezer that, if Ebenezer doesn't want to wind up in jail for kidnapping, he'd better agree to Davie's demands for money. So Ebenezer folds, and Davie ends the book a rich man.
However, as we discuss in "What's Up With the Ending?", the book more or less stops there. Does Alan Breck make it to France? Does Davie wind up going back to the Highlands to try to get Alan's cousin off the hook for the murder of Colin Roy? We don't know – unless we read Catriona, the sequel!