It's easy to find under the marble porch. The first boss is the kind where a monster flies in the sky with another monster and a gun. Lz is finished, go straight to the right, go up at the fork in the road, and you will get there easily. In order to open the mechanism leading to the groundwater vein, lz needs to move on, walk through the marble corridor, reach the outer wall on the edge of the cliff, defeat its own magic boss upwards, and continue to enter the library upwards. There is grandpa in the innermost part of the second floor. The first thing you can buy is the philosopher's stone that opens the magic door. Go back to a place on the right side of the clock under the marble gallery, open the door and step on the mechanism inside to open the groundwater vein.