When he returned to the common room, he found that Neville Longbottom was waiting up for him, looking sleepy and nervous. He jumped to his feet the second he saw Percy, and said a stream of mostly-incoherent words, the relevant bits of which were "Malfoy" and "reporting to McGonagall" and "huge trouble", and Percy sighed and patted the kid on the shoulder, pushing him gently towards the staircase to the dorms.