Final answer:
The sentence that shows how the setting impacts the plot is: "By the time we entered the classroom and everyone yelled 'Surprise!', I was loaded with six hefty novels to read."
Explanation:
The setting impacts the plot by initiating an unexpected consequence due to the protagonist's interaction in the teachers' lounge hallway. The setting, being in the vicinity of the English teacher's domain, leads Cayden to encounter Mr. Grayson and inadvertently engage in a conversation about literature. This interaction directly results in Cayden being loaded with six hefty novels, altering his summer plans.
The physical space of the hallway, where Cayden tries to execute the plan, intertwines with the unexpected encounter, setting off the chain of events that drastically change Cayden's summer agenda. Thus, the setting directly influences the plot progression, steering the story toward Cayden's unexpected reading list and impacting the outcome of his summer.