Regulus took a step inside as soon as the door opened, able to hear Draco's voice inviting him inside. He could tell, just by looking at his cousin, that the other probably hadn't been to bed just yet. In truth, Regulus was concerned, wondering just what the consequences of such actions were, but he tried not to let it show, kept a slight, yet crooked, smile fixated on his face as he moved completely inside the study.
"Morning, Draco," he repeated in return. He lowered himself into one of the chairs in the study, feeling comfortable enough to do so. "You're not terribly busy, are you?" he asked, eyes briefly scanning the top of Draco's desk. He rather suspected that whatever Draco's answer his cousin was more than sufficiently busy, but he did hope for a calm moment to properly discuss what was going on.