Where the key is and what it opens
The Storage Key is on a box near two enemies in the underground area behind a house near the Marketplace Lantern in Fallen Village. It opens the nearby storage-room door, letting you reach the weak point that clears the plague wall.
Chapter, Lantern and the correct house
Look for the key during Chapter 3: Rendezvous, in the Fallen Village region. Marketplace is the nearest Lantern. The house you want is the one a group of enemies is shooting at; its upper-floor balcony also lets you jump across to the Warrior’s Fury chest.
Find the Storage Key and clear the wall
- Enter the house that the group of enemies is shooting at in the village near Marketplace.
- Leave through the back of the house to reach the ladder leading underground.
- Climb down the ladder into the underground area beneath the house.
- Follow the passage around the corner to find a box near two enemies.
- Pick up the Storage Key from the box so you can unlock the nearby door.
- Open the nearby storage-room door with the Storage Key to gain access to the weak point.
- Destroy the weak point beyond the door to clear the plague wall.
If you picked up the Weathered Key
The Weathered Key is found on the ground behind the house with the crib during Lullaby. It opens a house across the river where you collect the Toy from a bed. For the underground storage-room door leading to the plague-wall weak point, use the Storage Key from the box.
Returning to Marketplace later
Fallen Village supports fast travel, so return to Marketplace when coming back for the key. You can revisit earlier areas after the story to collect missed items. Resting at a Lantern restores Health and Nephtoglobin and revives regular enemies, so be ready for combat on the way back to the house.