The story opens with Jim recalling and writing down the experiences he went through on a voyage to Treasure Island as a young boy. As requested by Squire Trelawney and Dr. Livesey, he takes up the task of recording all but one detail -- that of the true location of the island, as the treasure still remains buried there. So, Jim travels back in time and takes the reader to where it all started, to his father's inn -- Admiral Benbow. A lonely seaside inn located at Black Hill Cove, patronized mostly by local people and occasionally by seamen.
Of the many men visiting his father's inn, Jim's attention, one day, is captured by a old brown seaman wearing a soiled blue coat, with ragged hands, broken nails and a saber cut across one cheek, trudging towards the inn dragging a heavy sea chest. Jim notices that the seaman was whistling to himself and singing an old sea song. The song went :
"Fifteen men on the dead man's chest Yo-ho-ho and a bottle of rum.
Drink and the devil had done for the rest-Yo-ho-ho and a bottle of rum....."
Settling for a rum, served by Jim's father, the old seaman inquires about the cove. He decides to get a room at the Admiral Benbow after he finds out that very few people pass through. He chooses a room on the head of the inn to watch the passing ships and introduces himself as Captain.
The Captain's only concern is whether any seafaring men have passed by the road and whenever any new men stayed at the inn, he doesn't make his presence felt at all. Jim does not know anything about his new guest except that he has made inquiries to find out about the lovely inns along the coast. Jim gets to know him better when he is asked by the Captain to act as a sentinel for a monthly wage of a silver four penny. His task is to watch out for a "seafaring man with one leg". This strange request to look out for a strange man haunts Jim in his dreams.
Jim observes odd behavior by the Captain. Sometimes, after getting drunk, he sings his old sea song alone; and sometimes he wants other people to sing with him. The others all fear him, so they do as he requests. He often frightened the local people with stories about dreadful things in shockingly gruesome language. This also brings him his share of admirers who called him a true sea dog' and a real old sea salt'. Though Jim's father worried these new developments would drive people away from the quiet little inn, the Captain's tales brought excitement into the ordinarily calm life of the country folks.
His father's prediction does come true, though in a different way. Whenever the Captain is asked the rent money for his stay at the inn, he makes it clear that he has no money and has no intention of paying it either by any means. Neither does he open his old sea chest ever. Financially, the Captain was not well off. For as long as he stayed at the inn, Jim recalls, he had bought nothing except some stockings from a hawker. And his blue soiled coat is fully covered with patches.
Nobody dares challenge the Captain until, one afternoon, Dr. Livesey was visiting Jim's father who had recently become ill. He was waiting to see him, chatting with old Taylor on a new cure for rheumatics. He hears the Captain singing his song. Paying little heed to the song, he continues his conversation, which irritates the Captain who has demanded everyone's silence. Countering the Captain's shout in the most gentlemanly way, the Doctor makes him aware of the bad effects of drinking and indirectly calls him a scoundrel. Even when the Captain threatens him with a knife, the doctor maintains his composure. Responding to the threat, the doctor makes the Captain aware that he is liable to be punished for disturbing the peace. He concludes with a warning that the Captain will be under constant observation, as he (the doctor) is also a magistrate. The Captain, for the first time, is defeated.
As this story was written for a young boy, Stevenson has taken utmost care in building the character of the protagonist. He includes all the essential qualities that are required to make Jim Hawkins a model for all the young readers. In the opening line of the story the author introduces Jim as an obedient boy. Combining this with the curious nature of a youngster, the author sets the tone for the whole book.
While developing the plot of the book, Stevenson introduces us to two of the main characters and their characteristics: Jim Hawkins and the Captain.
Jim, as the narrator, tells the reader about the arrival of the brown old seaman at the Admiral Benbow. As the title of the chapter suggests, this chapter is a detailed recording of the incidents that takes place at the Admiral Benbow after the arrival of the Captain. From the very first glance, Jim says, he takes a dislike towards the old man with his old sea chest whistling and singing to himself. Jim gets to know more about him when he settles down at the Inn. At first, he finds him to be a silent loner who rarely speaks to anybody. As a drunk, the only company he seeks is rum. However his opinion changes with time and he begins to find the old man quite tyrannizing and eccentric after drinking. Jim also finds out that he is on the lookout for the seafaring man with one leg, a strange description that haunts Jim in his dreams.
A youngster's desire to possess money is established early by Stevenson when Jim accepts a part time job of keeping an eye for the "seafaring man with one leg."
Jim observes the old man's poverty. He forms his opinion about him being rude and tyrannizing when he refuses to pay rent to his father. Jim also grows inquisitive about the old sea chest, which always remains locked. He finds the old man cautious but fearless, at least until he encounters Dr. Livesey. His verbal confrontation with the doctor proves that the old man is fearful of the law.
When the first chapter ends, many qualities of the old man are described through his deeds, but his past, his intention of staying at the Inn, and the contents of his sea chest is kept a mystery. The quality of Jim as very keen observer is also clearly depicted. To maintain the mysterious environment that the author has created, he leaves the reader pondering over many unanswered questions.