A group of strangers in the late 1910s discuss the recent World War and its beginnings, arguing amongst themselves about what caused the world to descend into madness. One man speaks up, saying that he knows the cause very intimately since he was there in 1914 when it happened. He recalls an old friend named Gravilo, a Serbian man who spoke constantly of the Serbs' need for freedom. He would criticize the archduke and speak of revolution, but his wife, Mara, would shut him down immediately; she made him promise long ago that so long as he was devoted to her, he could not devote himself to a revolution, lest it separate them. Mara gets a bird one day and immediately Gravilo criticizes her for it, saying that this type of bird must be free, just like the Serbs, or else it will die in captivity. He urges her to let it go, but she says that sometimes a woman must make decisions for herself; she can't go living her life being told by her husband when to breathe in, when to breathe out. So she keeps the bird, and all the while a Serbian celebration is on the horizon. Gravilo asks if she'll let it out in celebration of the holiday, but she refuses, saying instead that she'll have a vet come and inspect it. In preparation for the holiday, the trio discusses the growing tensions in the area. The Archduke of Austria had been advised not to attend the celebration for fear of assassination. On the day of the celebration, the vet arrives, but the bird has already died due to parasitic vermin living on it, sending Mara into a spiral. She asks the visiting man to tell Gravilo. Unable to find him in his room, he wanders the town searching for Gravilo, only to stumble upon chaos when he learns that someone had thrown a bomb at the archduke during the parade. The archduke warded it off, but two horses died. He asks around about Gravilo, but no one has seen him. That is, until Gravilo steps out of the crowd and fires two shots at the royal couple, killing the archduke. The crowd is shocked to learn that the story they've been listening to has been about the murderer of the archduke. The man recalling the story tells them that the archduke's murder did not cause the war, nor did the bird—the war was caused by a small an actor as the parasites which killed Mara's bird.