Armando, a single teacher in his 40s, leads a methodical, safe and quiet life. He has no involvements, only some romantic adventures and is very dedicated to work. At school, he realizes that one of his students, Mário, is showing a decline in performance. He tries to find out the cause and discovers that the boy is in love with Laura, one of his colleagues. Armando then tries to talk to the girl and suggests that she stay away from Mário. But in this thorny mission, the teacher ends up becoming attracted to Laura himself.