Juan is a veteran workshop instructor with no formal education, but a lifetime of practical experience working on aircraft engines alongside engineers. His company sends him from Madrid to train at the Universidad Laboral in Córdoba. There, the master craftsman takes a young student under his wing. Disheartened by how poorly his first exams went, he considers giving up. But Juan advises him not to and helps him in every way he can. The two become friends, but one day the young man discovers the real reason behind Juan’s interest.