Climax. Just like the very top of a roller coaster is the most intense and scary part of the ride, the climax of a plot is the most exciting part of a story. The climax is usually a problem or difficult situation the main characters have to find a way out of.

climax, (Greek: “ladder”), in dramatic and nondramatic fiction, the point at which the highest level of interest and emotional response is achieved. In rhetoric, climax is achieved by the arrangement of units of meaning (words, phrases, clauses, or sentences) in an ascending order of importance.