About as well as she could hope

The cold water streamed over Hermione's body. She could feel the water rushing past her labia as she moved through the water. She didn't want to get too far from the shore, but also knew that grindylows lived in the weeds below the water, and she didn't want any long claws to grip her legs and drag her down, especially without her wand to protect her.

After she got to a point where she could no longer feel her feet touch the bottom and was out of an arms reach from any weeds, she looked back toward the tree. She saw that Daphne had caught up with her friends. They were all laughing and giggling, occasionally looking toward her naked self. Her clothes were still where she left them, at least.

She looked at the clock. 11:10. Still another 50 minutes of swimming to go. She didn't want to go terribly far from the tree, so she swam as best as she could to appease the trio, doing her best to keep her privates under the water surface.

Then it happened. She felt a hand on her ankle. "But I'm nowhere near the Grindylows!" Hermione thought to herself. Panic-stricken, she looked down to see what looked like a man, with the lower body of a fish. A merperson had gripped her and began to pull her towards the center of the lake, her head still above water!

Hermione used her arms to try to swim away as fast as she could, dignity be damned, but it was no use. The merperson pulled her further and further away from her clothes...

She was brought all the way to the Bowtruckle Island in the center of the lake, where the merperson released her. She looked down into the water and saw the merman just floating, watching, perhaps waiting.

"I... What do you want?" Hermione stammered out. She was afraid. She was naked, helpless, and at the mercy of whatever there was out here. She knew the merfolk respected Dumbledore, but she couldn't speak any mermish.

The merman evidently understood, as he grabbed her and **** her into the water down to her neck, then stopping. This gave Hermione enough time to take a deep breath before being dragged into the waters below.

"You are a woman ready to breed, are you not?" The merman asked.

"WHAT?" Hermione cried out, her sound muffled by the bubbles that came from her mouth.

He shoved her head above the water again to let her catch her breath before pulling her down again.

"Humans have a long history of crossbreeding with us Merfolk," he explained. "I can see you bare the signs of arousal of your kind. Wet that is not water, mammaries erect..."

Hermione stiffened, humiliated at the analysis the merman was giving her. She pointed to the surface, indicating that she'd like to talk. The merman let her up to respond. "I'll... I'll have you know that I'm simply cold! And how could you possibly know what liquids are here?"

He pulled her below again. "We can smell the liquids down here. Urine, ejaculate, water, blood... We can smell it all, and human female secretions are especially fragrant down here." He paused for a moment to let Hermione breathe again. "So if you're not here to lay your eggs for me to sew my seed onto, then why are you here?"

Hermione thought for a moment. "Do you promise not to tell anyone?"

"I can promise that this will not be passed on from merfolk to humans."

That's as good as she could hope. "Those Slytherin girls over there made me do this! I have to keep swimming naked until the clock strikes noon!"

The merman, for the first time, raised his head above water and looked over where he had taken Hermione from, before taking both of them under the water again.

"What girls?"