What fear does the narrator overcome while trying to solve the mystery of the dogs death in The Curious Incident of the Dog in the Night-Time book?

The narrator, Christopher, overcomes his fear of unfamiliar places and interacting with strangers as he investigates the dog's death. He pushes himself out of his comfort zone and navigates through the complexities of the mystery, gaining confidence and independence in the process. Through his journey, Christopher learns to overcome his anxieties and embrace new experiences.