On the eve of the 5 November, Catesby, Fawkes and the plotters load the tunnels below Parliament with barrels of gunpowder.
Across the city, Father Garnet is under pressure from an ally to break his seal of confession and reveal Catesby's plot - for the good of the Catholic faith. Will the priest be the one to betray Catesby at the eleventh hour? Or will Cecil need to find other means to destroy Catesby, win back the King's trust and save his life?