The TARDIS’s navigation falters once more, drawing it toward Earth and a situation involving "Duke Giuliano" (Gareth Armstrong), who has just come into his title and consequently made an enemy of "Count Federico" (Jon Laurimore). As is typical when time travelers appear, a puzzle unfolds, and the "Doctor" (Tom Baker) and "Sarah Jane" (Elisabeth Sladen) become entangled in the mystical dealings of the unsettling "Bret…