Where to Get the Prison Key
Get the Prison Key from the small chest beyond the Iron Key door in the forge/Jaguar corridor area, where it is stored with a Club. Use it on the locked Prison Door; reaching these locations involves the sewer Hammer, the forged Iron Key and the Small Key route from the hub.
Prepare at the Hub
Start from the main hub after passing the opening food gate and early Small Key lock. Your next prerequisite is the Hammer from the sewers, which breaks the rusty bars leading toward the forge. The Prison Key itself comes from a chest beyond the Iron Key door.
Bring food, a lit torch and spare Iron Rods and Chains for the prison. The torch clears spider webs, Iron Rods repair broken levers, and Chains repair the prison Mechanism. Leave room for the key and repair supplies before setting out.
Get the Hammer From the Sewers
- Craft a Rope from 2 Vines and 1 Stick in the Crafting menu if you still need to establish the sewer descent.
- Use the water wheel behind the hub stairs to lower the water and prepare the route toward the Hammer.
- Climb down the rope behind the hub stairs to enter the sewers. Use this descent as your landmark for returning to the hub.
- Swim past the eel with your stamina full to reach the rusty-pipe section. Recover before attempting the crossing if you have just been sprinting.
- Climb the rusty pipe to reach the Hammer at the end of the route. This is the tool needed for the rusty gates.
- Pick up the Hammer before returning to the hub. Finding it also unlocks its replacement recipe at the Workbench.
Forge the Iron Key and Find the Chest
- Break the rusty gate down the stairs to the right of the big door in the hub. This opens the route into the forge area below.
- Follow the opening on the left through the ceiling to reach the large smelter. This is where you cast keys using carried molds.
Carry the mold for the Iron Key to the large smelter. Move the mold into place as a physical object.Playing this video connects to YouTube.
- Supply the large smelter with 5 Coal and 8 Scrap Metal for the cast. Keep these materials available while arranging the mold.
Pull the smelter lever to produce the Iron Key. The finished key gives you access to the locked corridor needed for the Prison Key.Playing this video connects to YouTube.
- Open the Iron Key door in the forge/Jaguar corridor area. Be ready for the skeletons guarding the room beyond it.
- Take the Prison Key from the small chest containing the Club. You now have the key that opens the Prison Door.
Take the Staircase Route to the Prison Door
Collect the Small Key at the end of the sloping cave for the approach toward the prison. Bring it back for the locked route above the hub camp.Playing this video connects to YouTube.
Unlock the Small Key door above the main camp to continue along the route toward the prison.Playing this video connects to YouTube.
- Follow the upper hub route left and across the wooden plank to reach the spiral staircase.
Descend the staircase to reach the Prison Door. Keep following the lower route when the staircase offers an upward continuation.Playing this video connects to YouTube.
- Use the Prison Key on the inner Prison Door to enter. The route beyond continues through the prison camp and cells toward broken lever systems.
Open the First Route Inside
- Burn obstructing spider webs with a lit torch in your right hand. Torch damage clears these barriers so you can continue through the prison.
Check the prison's small chest for 2 Iron Rods and a Small Key. These supplies give you repair materials and another key while exploring the cells.Playing this video connects to YouTube.
Add an Iron Rod to the broken lever marked “Fix Lever.” Repairing it makes the lever usable for the onward door.Playing this video connects to YouTube.
- Pull the repaired lever to open the wooden door. The staircase beyond continues farther down through the prison.
- Supply Chains when the prison Mechanism displays “Bring Chains to Fix it.” This repair is needed alongside the raised Counter Weights to open the Big Door.
- Look for the Pickaxe on the lower prison route before continuing toward the upper boss area. It lets you break the yellow goo encountered during further exploration.
If the Key or a Door Is Holding You Up
If the expected Prison Key chest is empty, search adjacent rooms around the Iron Key corridor. Some key placements can vary. Keep your search focused on that area before retracing the entire Hammer route.
The Prison Key is kept on death, so check your inventory before returning to its chest. Inside the prison, the Big Door closes again after a while. Its mechanism requires Chains and raised Counter Weights, so inspect the repair prompt if pulling levers does not open it.