The climax of a story is the highest or most intense point in the development or resolution of something.
The climax of the story is in Part 6 when the pirates all find out that the buried treasure is actually missing. Long John Silver has lost control of his men pretty much at this point, and his men set out with the treasure map to find it. They try to overwhelm Long John Silver, Doctor Livesey, and Ben Gunn. But the retreat. Silver, Gunn, Livsley and Jim load the treasure on the ship and then leave the pirates behind.
The climax of the story is in Part 6 when the pirates all find out that the buried treasure is actually missing. Long John Silver has lost control of his men pretty much at this point, and his men set out with the treasure map to find it. They try to overwhelm Long John Silver, Doctor Livesey, and Ben Gunn. But the retreat. Silver, Gunn, Livsley and Jim load the treasure on the ship and then leave the pirates behind.