Dumbledore's start-of-term speech had the quality it always had — the specific warmth of someone who genuinely liked the people they were speaking to and found the occasion worth marking properly. He went through the usual structure: welcome back, welcome to the new students, staffing changes, the things worth knowing about the year ahead.
The Dementors warranted their own section.
"The Ministry of Magic," Dumbledore said, with the careful precision of someone choosing every word deliberately, "has stationed Dementors at the boundaries of Hogsmeade village for the duration of this period of heightened security. They will conduct searches of the Hogwarts Express at the start and end of each term." He paused, and the pause looked like an old man who had spent a long time thinking about how to say what he was about to say. "They will not be stationed on school grounds. I have been very clear with the Ministry on this point, and we have arrived at an agreement that I find adequate and that I will be monitoring carefully."
The Hall received this with the uncertain quiet of people who had information they didn't know the full weight of yet.
"I would ask all students to remain within the school grounds outside of organised Hogsmeade visits. When those visits do take place, prefects and staff will accompany all groups at the village perimeter. The Dementors' effect can be mitigated, and the staff who will be accompanying you have been briefed accordingly." He looked out at the Hall with the steady attentiveness of someone watching for specific faces. "Should any student find themselves in proximity to a Dementor outside of those controlled circumstances, the correct response is to move immediately toward the nearest lit and populated area and to report the encounter to a member of staff."
His eyes moved, very briefly, to where Harry was sitting. Harry's expression had the quality of someone who had been given information he already had via a harder method and was receiving the official version with the patience of someone who could afford to.
"The Patronus Charm," Dumbledore continued, "is the effective defensive response to Dementor exposure. It is challenging magic — above the level we would normally teach in the general curriculum — but it is not beyond determined students. If any of you wish to learn it, I would encourage you to speak to Professor Lupin, who has considerable expertise in this area." He smiled, fractionally, in the direction of the staff table. "He is, I understand, a willing teacher."
Lupin, at the staff table, had the expression of someone who had been briefed on this mention and had accepted it with the quiet resolution of someone who had decided what their priorities for the year were.
Ron took a photograph of the staff table — Lupin at the end of it, looking out at the Hall with the expression of someone who had arrived somewhere they had not expected to arrive and was still determining what that meant. It was not a dramatic photograph. It captured something true, which was worth more.
"Finally," Dumbledore said, "it is my very great pleasure to introduce Professor Lupin, who joins us this year as Defence Against the Dark Arts professor. Some of you will have encountered him on the train this evening. Those who did not will have the opportunity shortly." The pause of someone who had been making speeches for over a century and understood the value of the beat before the last line. "I suspect you will find the experience worthwhile."
He thought about the compartment and Harry's face and Lupin saying it would have been good with twelve years of weight in it, and thought that worthwhile was a significant understatement but would serve.
The feast arrived properly then — the tables filling with the specific abundance of a school that understood that returning was an occasion — and around him the Great Hall became what it was supposed to be: warm and loud and full, the four houses occupying their respective territories with the comfortable familiarity of people who knew exactly where they belonged.