What is the main conflict in Haroun and the Sea of Stories by Salman Rushdie?

Salman Rushdie's Haroun and the Sea Stories is a shows a depressed professional storyteller and his adolescent son traveling to Earth's second, invisible moon, where all stories are born. They foil the poisoning of the Ocean of the Streams of Story and rescue a kidnapped Princess, get back the father's gift of gab, and see their family reunited.