Much of the running time of Voyage to Italy is uneventful. The opening scene shows Katherine and Alex Joyce simply conversing as they drive through the Italian countryside; the only incident is momentary, when they slow for a herd of cattle in the road. Shortly after they arrive in Naples, the film follows them as they are given a lengthy, room-by-room tour of Uncle Homer's villa by its caretakers, Tony and Natalie Burton. The film subsequently follows Katherine on several days as she tours Naples without Alex. On the third day of her visit, she tours the large, ancient statues at the Naples Museum. On the sixth day she visits the Phlegraean Fields with their volcanic curiosities. On another day she accompanies Natalie Burton to the Fontanelle cemetery, with its stacks of unidentified, disinterred human skulls that are adopted and honored by local people.