In DOOM: The Dark Ages, Chapter 10, titled "Forsaken Plains", marks the first full descent into Hell. This chapter introduces a unique level design centered around a massive structure called the Atlan, which connects three distinct zones. This architectural layout not only enhances exploration but also simplifies navigation, especially when searching for hidden collectibles like the Secret Key.

The Secret Keys in this game are crucial items that allow players to access restricted areas sealed behind purple energy barriers. Chapter 10 features one such key, and unlocking it opens the door to several bonus rooms filled with rewards. If you haven't experienced this chapter yet, you can buy Doom: The Dark Ages account at Z2U to jump right into the action and enjoy everything Chapter 10 has to offer.

Step-by-Step: How to Obtain the Secret Key
To begin your search, proceed through the level by following the main mission markers until you pass through the initial gate. Once you reach the open area featuring a large, ruined Atlan structure, head down the left path. You'll soon notice a secret door, but save that for later—your priority now is the key.

Keep on until you see the Secret Key hovering next to a tall tower in a holographic projection. Unfortunately, you can't reach it directly from the ground. Instead, you must ascend the tower from the rear.

Look up at the back side of the building to find a green grapple point. Use your Saw Shield to attach to it, then activate the shield again to climb upward. At the top, gather nearby armor pickups, then target a section of glowing hot metal across the gap and throw your Saw Shield to clear a path.

Follow the trail of Gold pickups, carefully avoiding fire traps along the way. You'll encounter a heavily armored demon—defeat it and continue down the hallway. When you exit outside, locate a climbable wall on your right.

Jump up and grab a Gold Chest, then leap across a gap to reach a walkway circling the tower. From here, drop down into the center of the tower to finally retrieve the Chapter 10 Secret Key.

Using the Key: Unlocking All Secret Doors in Chapter 10
With the key in hand, you can now access three secret doors scattered throughout Forsaken Plains:

1. Hidden Area Near the Fallen Atlan
This door is located just to the left of the fallen Atlan, tucked into a sunken zone beneath rocky cliffs. Outside, a Sentinel statue holding a Ruby stands guard.

Inside: A combat arena awaits. Defeating all enemies removes the red barrier around the statue, allowing you to claim the Ruby.

2. Door Close to the First Hell Cannon
After using the Shield Charge to destroy the first Hell Cannon, continue toward your next objective. The second secret door will be along your route.

Inside: Collect multiple Gold pickups, another Ruby, and navigate around dangerous flame hazards.

3. Courtyard Behind the Central Atlan
This last hidden spot is in a peaceful courtyard area behind the main Atlan. On your minimap, follow the line of Gold pickups leading to a hidden Codex item.

Inside: Grab several Gold pickups and the Prince Ahzrak Codex.

Final Thoughts

Chapter 10 of DOOM: The Dark Ages offers an intense yet rewarding experience as you explore the chaotic landscape of Hell. Locating the Secret Key early allows you to uncover powerful bonuses and secrets that enhance your gameplay. For those looking to get started quickly, there are cheap Doom: TDA accounts for sale that can give you immediate access to later chapters like this one.