A Good Girl's Guide to Murder is a novel by Holly Jackson. The story is about a 17-year-old high school student named Pippa Fitz-Amobi, who decides to investigate a murder that happened in her small town of Little Kilton five years ago for her senior year project.
The murder victim was a popular high school student named Andie Bell, who was purportedly killed by her boyfriend, Sal Singh, who then committed suicide. However, Pippa is not convinced that Sal is guilty, and she sets out to prove his innocence.
Pippa's investigation leads her to interview people who knew Andie and Sal, including Andie's friends, family, and former classmates. She discovers that there were a lot of inconsistencies and unanswered questions in the original investigation. She also finds new evidence that suggests that someone else might have been involved in the murder.
As Pippa gets closer to the truth, she puts herself in danger, and the killer becomes aware that she is onto them. However, with the help of her friends and family, Pippa can solve the case and bring the real killer to justice. Along the way, however, she uncovers a web of corruption in her town's government.
In the end, Pippa discovers that Sal Singh is not the killer of Andie Bell. She uncovers evidence pointing to Andie's best friend, Becca, as the killer. Becca had become jealous of Andie's relationship with her boyfriend, and her obsession and envy drove her to commit the murder. Pippa gathers the evidence and confronts Becca with it, leading to Becca's eventual confession and arrest for the murder of Andie Bell. Pippa's dedication to the case and her investigative skills ultimately helped bring justice to Andie's family and exonerate Sal.
