Lydia watched with horror as a swarm of grindylows entered the cave. She still floated just outside the cave's entrance, among the forest of seaweed. Suddenly everything was chaos. The grindylows were attacking everyone in the cave, including the professor who had just raced toward them from the merpeople's village.

An older Hufflepuff boy--she thought he was a Prefect--had exited the cave a few moments earlier to tell everyone to swim away but when the grindylows attacked he'd gone back inside, presumably to help the other students and the professor. She watched him do battle with the grindylows. He was holding his own until one of them chomped down on his thigh, and he started yelling instead of firing off spells.

Biting her lip, Lydia hesitated but only for a moment. She really didn't want to see this boy become lunch right in front of her. With a powerful kick of her fins, she flew through the water toward the Hufflepuff, withdrawing her wand from its holster as she did so. As a first year she didn't know many spells, but she did know one that would be useful, one the boy had been using earlier.

Aiming directly at the grindylow attached to the boy's thigh, she cried, "Flipendo!" She could feel the power travel through her arm and through the wand. The grindylow was sent catapulting backward and away from the Hufflepuff.

With her good deed for the day accomplished, Lydia turned right around to make her own escape before one of the grindylows wanted her for a snack next! At the very exit of the cave though she paused, her eye caught by the treasure once more. She dived and scooped a giant shiny coin into her hand. There. At least this would make the whole disaster worthwhile!