Critical thinking plays a crucial role in children's education for fostering cognitive development, cultivating independent thinking habits, and enhancing their ability to problem-solving. However, the current educational model places greater emphasis on children's understanding of factual knowledge, with relatively less focus on developing critical thinking skills. We present CharacterCritique to support children's critical thinking based on the theory of inquiry dialogue. This tool uses an analytical story as the medium, it encourages dialogue between parents, children, and story characters. Through this process, children continuously engage in interpretation, analysis, explanation, evaluation, and regulation, all of which promote critical thinking and decision-making. Such interaction is supported by multiple agents. In our between-subjects study (n=32), we compared CharacterCritique to traditional storybook reading. The results show that CharacterCritique is more effective at sparking children's interest in deeper discussions. It also better fosters critical thinking, problem-solving skills, and creates more opportunities for parent-child dialogue.