How to Shoo the Death’s-head Moth

Widowed grammar school teacher Kalousek, nicknamed by the students Smrtihlav (Death's Head Moth) because of his passion of entomology, collects at the waste-rock of a new open-cast mine minerals for his collection. He is captivated by a lamp to which the night-butterflies, another object of his collecting interest, are flying surely at night. The student Petr Loriš has little or no vocation for studying, rather he is entertainer of the class and Kalousek threatens him with the lowest mark and fail. Kalousek's son Jirka with his wife at last has got a new flat and the teacher is looking forward to get new space to his collections. But, in a shock, he finds out at a decree of a flat a signature of the new chairman of a housing association – Loriš – and he is at once persuaded that the point is, in fact, bribe. He forces the young couple to return the flat. But his daughter in law makes him believe it is out of the question – namely she is with child. Enthusiastic future grandfather soon finds out it is a lie, to be sure the daughter in law smoked and she drank with celebration by Champagne. He takes deadly offence at his son and daughter in law. He purposely examines Petr at the presence of the headmaster of the school who consents with student's failure. But son Jirka makes the professor do a bit of thinking over his distance from life of his students. Kalousek invites Petr to his home and makes an offer to prepare him for a reexamination. The student is grateful for he lacks the true interest of an adult – including his own parents.