The arrival of the TARDIS in Paris, France in 1572 places its occupants, the First Doctor and Steven, in a dangerous situation. Tensions between the Protestant Huguenots and Catholics are at fever pitch in the city. Despite the danger, the Doctor heads off alone to visit the apothecary Charles Preslin, leaving Steven alone. Steven enters a tavern and meets Nicholas Muss, a Huguenot. When the Doctor does not return as arranged, Steven decides to spend the night at the home of his new friend. While Steven and Nicholas are wandering home, they find a frightened serving girl, Anne Chaplet. Anne is terrified because she has overheard some Catholic guards speaking of a coming religious massacre of Huguenots here in Paris. To protect her and her knowledge, Nicholas arranges for Anne to go into the service of his master, Admiral Gaspard de Coligny.