MTL - Harry Potter’s Book of Sin - Chapter 14 Hogwarts at Night

... , some are talking to the whisperers next door, and others seem to be going out, leaving only the background on the paintings.

On the eighth floor, in the Gryffindor common room, the students have already returned to the dormitory to sleep, but the remaining fire in the fireplace is flashing a faint red light, which dimly lights the entire lounge.

As Harry and Ron stomped past an armchair, they suddenly heard someone talking there.

"I can't believe you did this, Harry."