After spending a full week alone in the Room of Requirement, Harley finally left one night.
But Harley didn't return to the Gryffindor common room. Instead, she headed straight for the Black Lake.
It was already March, and the weather had turned clear.
That made Harley's plans much easier. After all, the stars had been coming out much more often.
According to Harley's calculations and Divination, the most brilliant starlight would come in a few days. It would be the best time to observe that magical black tree.
Before then, Harley needed to visit the Merpeople Village and the Unicorns' settlement.
It was late at night, and many intelligent beings were asleep, but the Black Lake teemed with life.
The giant Cuttlefish, usually sluggish during the day, were now full of energy. They hunted all kinds of fish in groups, occasionally startling a few Grindylows.
The two sides would sometimes fight briefly over their prey, but soon they would go their separate ways again.
Harley didn't disturb them. She didn't even use Cursed Transformation to turn herself into a Golden Merperson.
This time, Harley chose to dive using a Warming Potion, a Waterproofing Potion, and an Underwater Breathing Potion.
This method slowed her down considerably, but it ensured she wouldn't make a commotion and attract too much attention.
Thanks to Harley's caution, she reached the Merpeople Village without incident.
Two large Grindylows were still tethered at the village entrance, like guard dogs kept by wizards.
But Harley was already invisible, and she could also use an Assassin's abilities to conceal her presence.
So the two Grindylows noticed nothing. They simply stared foolishly at the waterweed swaying in front of them.
Most of the Merpeople were asleep as well, allowing Harley to reach Merpeople Square without trouble.
The square was empty,