A teacher, protesting the Board of Education's inattention to her cries, takes the board hostage at gunpoint and Mannion is called in to diffuse the situation. Frustrated by getting the run-around from the board and environmental agencies, she gives Mannion 12 hours to find answers to the teacher's and students' health problems before she opens fire. Mannion and his team must uncover a complex environmental cover-up while keeping the board and the teacher alive. Meanwhile, Ella asks Clive, the new man she is seeing and a lobbyist for the chemical industry, to look into the case from his end.