Beatrice LaCroix was just a young special education teacher before her principal was brutally murdered behind locked doors. In "The Last Day of School" Bea's good friend is accused of the murder and Bea must turn detective in order to clear his name. She teams up with two friends, a cop and a fellow teacher, to interview staff members, follow people incognito, and wade through the physical evidence that is discovered. Her science-driven brother joins in the search for the true killer, lending his lab and high tech equipment to the home-grown detectives.