In the summer of 1936, before the outbreak of the civil war that plunged Spain into three years of agony and terror, 8 year old Moncho is beginning his first day at school. At first afraid of his new teacher, Don Gregorio - who he had heard flogs pupils - teacher and pupil soon develop an inseparable bond, born of their shared interest in insect life. So begins Moncho's apprenticeship into life and knowledge guided by his worldly teacher. But as the military marches through Spain and the community is split in two, their friendship is put under unbearable pressure. Butterfly's Tongue us a beautifully shot film about the lessons of life that cannot be taught in school.