“But then . . . ,” Lupin muttered, staring at Black so intently it seemed he was trying to read his mind, “. . . why hasn’t he shown himself before now? Unless” — Lupin’s eyes suddenly widened, as though he was seeing something beyond Black, something none of the rest could see — “unless he was the one . . . unless you switched . . . without telling me?” Very slowly, his sunken gaze never leaving Lupin’s face, Black nodded.
