Prompt: You decide to take the path on the right and explore the mysterious area by the lake. The path leads to a dense thicket of trees, gradually becoming heavily shaded. When you pass through the bushes, you find a bright opening ahead, as if leading to another world. After crossing through the opening, you arrived at a dark cave. In the depths of the cave, there is a huge blue crystal emitting a faint light. Suddenly, a mysterious voice echoed in the cave. Mysterious voice: \"Adventurer, you have come to the depths of Crystal Lake. Solve the mystery here, and the frozen lake water will open the door to your next trial.\" You noticed some strange runes scattered on the ground, seemingly clues to a puzzle.