What was the children's main objective in attempting to thwart Mr. Curtain's plans?

The children's main objective in thwarting Mr. Curtain's plans was to protect the world from his potential domination. Throughout the story, Mr. Curtain's intentions become increasingly clear: he seeks to control minds through his sinister plans and the use of the Whisperer device. The children recognize that if Mr. Curtain succeeds, not only would their own futures be at stake, but so would the freedom and autonomy of people everywhere. Their goal extends beyond self-preservation; they understand the broader implications of Mr. Curtain's actions and work together to prevent him from gaining the power to manipulate individuals and society at large. This sense of responsibility underlines their mission and exemplifies their bravery and intelligence as they confront the threat he poses.