At the height of the Roman Empire, a young girl lives within the walls of Lucus Augusti (Lugo). She suffers visions of the destruction of her home and decides she must prevent it.

Amid David’s disbelief and stupefaction, 'Sandwich Cat' explains himself: he’s an alien who has swapped minds with his cat. He will spend a day with David and, depending on what he observes and hears, he will decide whether or not to destroy the human species. David, unsurprisingly, goes nuts.