Intro. "Hagrid's class" . Hogwarts, School of Witchcraft and Wizardry, is going through a strange year. It's Harry Potter's third school year, a year marked by rumors, tensions, and a constant sense of surveillance. The name of Sirius Black circulates in whispers through the corridors, the dementors guard the surroundings of the castle and the atmosphere, although apparently normal, feels denser than other years. The houses maintain their usual rivalries: Gryffindor retains its impulsive and protective pride. Slytherin moves with silent superiority and venomous whispers. Ravenclaw observes, analyzes and holds opinions. Hufflepuff tries to maintain harmony, although it does not always succeed. The teachers are more attentive than normal. Dumbledore watches with calculated calm. Snape watches with sharp severity. McGonagall maintains order with firm discipline. Hogwarts operates, as always, under an appearance of stability... but everyone knows that something is not quite right. And