This walkthrough will guide you through all objectives of the side quest Cache in the Castle in the game Hogwarts Legacy.
How to start the Cache in the Castle Side Quest
Requirement: The quest is available after you have finished the Main Quest: Welcome to Hogsmeade
To initiate the quest head to one floor above Professor Fig’s Classroom and talk to Arthur. Arthur has two treasure maps and wants to give you one of the treasure maps so you can discover where it leads.
Talk to Arthur Plummly
You can find Arthur Pummly next to the large statue outside the Charms Classroom in The Astronomy Wing. It is one floor above Professor Fig’s Classroom. Arthur will provide you with one of the treasure maps. The treasure map’s three main features: A Rhinoceros statue, A Dragon fountain, and a Door. To find the treasure, you’ll need to visit each of these three locations.
Find the first landmark from Arthur’s Treasure Map
The first landmark given in Arthur’s treasure map is a rhinoceros skeleton. It is located on the lower floor of the Defence Against the Dark Arts area in The Astronomy Wing. You just need to go down the stairs in front of Arthur.
Find the second landmark from Arthur’s Treasure Map
The 2nd landmark given in Arthur’s treasure map is a dinosaur skeleton. It can be found in the Transfiguration Courtyard of The Astronomy Wing. Dragon fountain statue right in the middle of the courtyard.
Find the third landmark from Arthur’s Treasure Map
The third and final landmark shown in Arthur’s treasure map is a painting located in the North Hall stairwell. Follow the quest marker behind the dinosaur statue and go through the large door to enter North Hall. Head up the stairwell to the right to find the painting on the wall.
Find the painting from Arthur’s Treasure Map
The third landmark and painting on the wall of North Hall are the same here.
Discover the painting’s secret
Use Accio toward the handle at the top of the painting to reveal a hidden room with a chest inside.
Return to Arthur Plummly
Finally, return to Arthur in the same spot near the Charms Classroom.