Haneul Nuclear Reactor in MW4 DMZ: an atom sculpture in front of two cooling towers in radioactive fog — Screenshot: Call of Duty: Modern Warfare 4 © Activision (enhanced)

MW4 DMZ Story Mission · Haneul Nuclear Reactor

Operation Fallen Ember Walkthrough in MW4 DMZ

Operation Fallen Ember is a Story Mission at Haneul Nuclear Reactor with 5 objectives, all listed below in order. It pays Reactor DRC Locker key, Cargo Plane (Paid Infil) and 25,000 DMZ Cash.

Last updated October 23, 2026Game version: DMZ Early Access, day 2

◆ Fortress · ■ Compound · L Lieutenant Tower · U UAV Tower · A Ammo Armor Cache · G Gas Station · M Marine Gas Station. Rings show the highest threat level (Low, Medium, High, Critical, Extreme); the white ring is Haneul Nuclear Reactor. Smaller markers from Activision's official Hajin Tac Map. Screenshot: Call of Duty: Modern Warfare 4 © Activision (enhanced)

Objectives

Collect gas masks first: the compound outside the reactor has them, and the hazmat enemies drop them
Get into the reactor
Pull 3 fuel rods from the pool: a teammate at the computer reads out where each one is, and it changes every match
Decontaminate the fuel rods
Take the patrol boat to the helicopter and see it off

Confirmed by 2 sources: video 1 at 7:26, video 2 at 22:03. Checked 2026-10-21 (DMZ Early Access, day 2).

Before you go

The final Story Mission. Threat assessment Extreme; recommended gear: a 3-Plate Armor Vest, a Medkit, a Gas Mask and Radiation Blockers. The mission screen lists three objectives: Breach the Reactor, Secure the Rods and Extract Decontaminated Rods. The pool is irradiated, so bring more than one gas mask each.

Rewards

Reactor DRC Locker key: where it is used and what players found behind the door
Cargo Plane (Paid Infil): see every DMZ vehicle and what a Paid Infil costs
25,000 DMZ Cash

Where Operation Fallen Ember takes place

Operation Fallen Ember runs at Haneul Nuclear Reactor, where the highest threat level listed is High. See it on the interactive Hajin map; our Haneul Nuclear Reactor location guide has the threat level of each area and the keys whose doors are there.

When it unlocks

It is the last Story Mission: it opens once you have finished Operation Iron Citadel and Operation Grid Assault. Only one squad in a match can run a given Story Mission, but other squads can still come after you there. You can replay Story Missions.

Questions

Where is Operation Fallen Ember in MW4 DMZ?

At Haneul Nuclear Reactor, where the highest threat level listed is High.

How do you complete Operation Fallen Ember?

Finish its 5 objectives in order: Collect gas masks first: the compound outside the reactor has them, and the hazmat enemies drop them; Get into the reactor; Pull 3 fuel rods from the pool: a teammate at the computer reads out where each one is, and it changes every match; Decontaminate the fuel rods; Take the patrol boat to the helicopter and see it off.

What does Operation Fallen Ember reward?

Reactor DRC Locker key, Cargo Plane (Paid Infil) and 25,000 DMZ Cash.

When does Operation Fallen Ember unlock?

It is the last Story Mission: it opens once you have finished Operation Iron Citadel and Operation Grid Assault.

The other Story Missions

Operation Critical Extraction (Mirae General Hospital)
Operation Silent Ledger (Cheongun Village)
Operation Shopping Hacks (NuriGO Mall)
Operation Iron Citadel (Chang-san Air Base)
Operation Grid Assault (The Grid)

Tick off every objective, and the DMZ Orders at the FOB, in the MW4 DMZ missions checklist.

Sources

Checked against the official posts on October 21, 2026. The objectives and rewards come from players' videos of the mission, linked above at the moment they show them; a mission gets its own page once two different sources agree.