Complex sentence: Hiding inside her father's house, Tiffany finds her pendant inside a fish her brother, Wentworth, caught and puts it back on when the service of a witch was needed by her father and people of the Chalk.
Split into simpler sentences: Hiding inside her father's house, Tiffany finds her pendant inside a fish her brother, Wentworth, caught. She put the pendant back on when the service of a witch is needed by her father and the people of the Chalk.