A Good Girl’s Guide to Murder follows high school senior Pippa Fitz-Amobi, who decides to investigate a five-year-old local murder case for her final school project. Everyone in her town believes that Andie Bell was killed by her boyfriend, Sal Singh, who then committed suicide. However, Pippa isn’t convinced and starts uncovering secrets that someone in town is desperate to keep hidden. As she gets closer to the truth, her own life begins to be in danger.