"Hurry up," Aberforth urged, leading Nelson onto the little wooden boat beside the Black Lake dock and telling Ogg to row for the opposite shore. Driven by magic, the small boat cut through the wind and waves, leaving a blade-thin ripple across the vast, calm surface of the Black Lake. "Sorry to trouble you."
"It's no trouble, Professor Dumbledore." Ogg steadied the oar with one hand and gripped Nelson's shoulder with the other, keeping him from losing his seat in the jolting boat as he gazed out at the mist-shrouded lake ahead. "If you need anything, just say the word."
"What happened, Professor?" Nelson was left dizzy by Aberforth's sudden move, and a faint unease crept over him. He hesitated before asking, his voice gradually turning urgent and sharp. "Did something happen at home? What happened to my aunt?!"
"Your aunt is fine. I'll explain slowly once we're on the train." Aberforth's face was tight, revealing not the slightest hint of what he was thinking. Nelson could only force himself to calm down and watch the bow cut through the water, weaving through the fog. Yet the closer they came to shore, the more restless he became. He felt as if a piercing rhythm were stabbing into his mind, like fingernails scraping across a blackboard, or a rusty gramophone singing at the top of its lungs. He held down his agitation and unconsciously covered his ears with his hands.
"That's the mermaids singing." Ogg's voice sounded above Nelson's head. Nelson looked up and saw that the worry on Ogg's face was no less than Aberforth's. Ogg muttered to himself, "What's going on? They usually don't come up to the surface to sing."
The grating song gradually faded away. In the end, Nelson never caught a glimpse of what the mermaids