In the book "The Red Pyramid" by Rick Riordan, Sadie demonstrates her confidence and determination by comforting her Uncle Amos with a kiss on the forehead and assuring him that she has a plan. This simple yet intimate gesture illustrates their close relationship, as well as Sadie's proactive nature. Her words suggest she is ready to take charge of a challenging situation.

The narrator's reaction to Sadie's declaration shows a sense of concern and foreboding, implying that her plan might lead to unforeseen consequences. The combination of Sadie's optimism and the narrator's caution sets a tense atmosphere, hinting at the adventure and challenges that are to come as they face the unknown together.