The carabinieri are on the trail of Fra Diavolo, a notorious bandit and his companions. Fra Diavolo appears at the local inn, disguised as the Marquis de San Marco and attempts to steal money from Lord and Lady Cockburn who are staying at the inn. But en route to Lord Cockburn’s room, Fra Diavolo is discovered – still in disguise – in the bedroom of Zerlina, daughter of the innkeeper and lover of the carabinieris’ leader Lorenzo. Lorenzo challenges the ‘Marquis’ to a dual. But before the dual takes place, Fra Diavolo’s true identity is revealed. Before Fra Diavolo is shot, he admits Zerlina’s innocence, to Lorenzo’s great satisfaction.