December 1924, Karl Denke fails to smite Vincenz Olivier with a pickaxe. He would have been his 31st victim. The film thus reconstructs the mind, motivation, and psyche of its main character in intense dialog between him and the inspector.
Felipe just wanted peace, to enjoy his July vacation away from school and, his classmates, and their cruel nicknames about his weight. The problem is that his mother decides to host Caio, his neighbor and former friend, for fifteen days. Caio, who is now a annoying teenager, brings out Felipe's insecurities. Over time, Felipe's resentment toward his neighbor turns into friendsh...