"The Good Girl's Guide to Murder" is a young adult mystery novel by Holly Jackson. It follows the story of Pippa Fitz-Amobi, a high school student who decides to investigate a closed murder case involving a local boy, Sal Singh, who was accused of killing Andie Bell. Pippa believes he was innocent and sets out to uncover the truth. As Pippa delves deeper into the investigation, she uncovers secrets and lies that challenge her perceptions of her community and the people around her. The novel explores themes of truth, justice, and the impact of social media on public opinion.