Young Jessica Fletcher's life couldn't be more ordinary. She teaches at the local high school while she and her loving husband, Frank, are raising their nephew Grady together. But when the beloved principal dies under mysterious circumstances, Jessica knows something is off and, for the very first time, investigates a death. Present-day Jessica returns to high school for a former colleague's retirement party and has fun seeing familiar faces. That is, until the colleague winds up dead - and his death has mysterious links to Jessica's first murder case.