At 12 Grimmauld Place, Sirius Black, who had just been on night watch duty, realized something was wrong after receiving Phineas's alert.
Even if the Dark Mark had appeared at the Astronomy Tower, even if Death Eaters had truly infiltrated Hogwarts, it was nothing much in the face of Dumbledore, who had already returned to the school. He could handle most matters himself.
Yet the headmaster had still asked Phineas to remind the Order of the Phoenix members to reinforce Hogwarts. That meant Hogwarts might truly be in serious trouble and needed extra hands.
Sirius immediately contacted the other Order of the Phoenix members through the Communication Bookmark, telling everyone to gather at 12 Grimmauld Place. Unfortunately, most people had already gone to bed at this hour. In the end, only Lupin, Bill, and Fleur, whom Sirius had personally gone to notify, hurried over.
The others had either gone to Azkaban or could not be contacted for the moment.
After discussing it, the four unanimously decided that Fleur would remain at headquarters to wait for the other Order members who might arrive, while the rest immediately used Floo Powder to reinforce Hogwarts.
On their way to the Astronomy Tower, they ran into Professor McGonagall.
"What's the situation now?"
Sirius caught his breath and asked Professor McGonagall.
"I don't know. Harry just came to tell me that the Dark Mark had appeared at the Astronomy Tower and that Death Eaters had infiltrated Hogwarts. I'm still completely in the dark."
Professor McGonagall could not help but breathe a sigh of relief when she saw Sirius, Lupin, and Bill. She, too, realized that something was wrong.
The sounds coming from the Astronomy Tower made the four immediately stop talking and listen with heightened vigilance.
Bill's eyes widened in shock as he murmured, "Could