Detonating The Nucleus & Destroying Acadia in Episode 10 – Fallout 4 Walkthrough
In this part of our Fallout 4 walkthrough, we reach the dramatic end of the Far Harbor DLC. After making it through the tough initiation in the radioactive fog, we finally get full access to the Children of Atom’s inner sanctum. What starts as a secret infiltration soon turns into a large-scale battle across the island. We discover the truth about DiMA’s actions, find a pre-war nuclear launch key, and defeat the rival factions to end the conflict.
The Faraday’s Program & Captain Avery’s Grave
We enter the large, irradiated cavern where the USS Democracy is located and head up to meet High Confessor Tektus. After passing the initiation, he trusts us and lets us access the submarine’s command center. We use Faraday’s Program on the main terminal to get past security. To keep this walkthrough moving, we skip the usual memory puzzle minigame and go straight to the decrypted data. This gives us the coordinates for a secret facility under the Vim! Pop Factory and the location of the nuclear launch key codes.
We leave The Nucleus and make our way through the fog to the Vim! Pop Factory. The building is full of Super Mutants, so we have to fight our way inside. After getting through the factory’s old conveyor belts, we find a hidden basement where DiMA carried out secret experiments. There, we dig up an unmarked grave and find the real Captain Avery’s remains and her silver locket. This proves that DiMA killed the founding leader of Far Harbor and replaced her with a synth to control the town.
- Lore Fact: Vim! Pop was a highly popular regional soft drink in Maine before the Great War, serving as a bitter corporate rival to Nuka-Cola. The factory’s basement was originally a corporate espionage bunker used to hide stolen formulas before DiMA repurposed it into a secret, isolated medical facility.
Confronting DiMA & The Nuclear Launch Key
With Captain Avery’s locket in hand, we fast-travel back to Acadia’s observatory to confront DiMA. When we show him the proof of his crime, DiMA struggles to explain how he can claim to be peaceful after committing murder and erasing the memory. We don’t accept his excuses and instead talk to Kasumi Nakano, letting her know the truth is out. Now, we focus on getting the launch codes to stop the Children of Atom for good.
To get the physical key, we first need to find the encrypted coordinates in the Harbor Grand Hotel. We break into a safe room in the lobby and listen to a pre-war holotape that sends us to Fringe Cove Docks. At the shore, we fight off toxic Anglers with our shotgun, then put on our aquatic gear and jump into the cold, irradiated water. Using our Pip-Boy light, we find a sunken fishing boat, open a wall safe, and finally get the Nuclear Launch Key, giving us control over the island’s fate.
- Lore Fact: The nuclear launch key was originally stolen by a defecting naval officer from the USS Democracy who realized the absolute horror of launching a nuclear payload. He attempted to flee the island via Fringe Cove Docks but was ultimately hunted down and killed, leaving the key stashed at the bottom of the ocean for over two centuries.
Detonating The Nucleus & Richter’s Final Stand
With the launch key secured, we immediately teleport back to The Nucleus to execute the “Cleansing the Land” questline. Bypassing the fanatic crowds in the lower decks, we sprint straight into the command center and aggressively override the security procedures. We insert the launch key into the main console and authorize the immediate detonation of the submarine’s nuclear warhead. Klaxons begin blaring, and emergency red lights bathe the rusted interior in a terrifying glow. We have only seconds to evacuate, forcing us into a frantic, high-stakes sprint out of the submarine base, entirely ignoring the panicked screams of the zealots trapped inside.
Bursting through the heavy exterior blast doors, we run a safe distance into the woods just as the nuclear warhead detonates. The visual show of the atomic blast is absolutely breathtaking, sending a massive shockwave through the pine forest and permanently vaporizing the cult’s stronghold. However, the fight isn’t over. Grand Zealot Richter and a small squad of surviving guards immediately ambush us outside the blast zone. We draw our weapons and engage in a brutal, final firefight, efficiently gunning down the heavily armored commander and looting his unique gear, permanently eradicating the radioactive cult from Far Harbor.
Kasumi’s Return & The Nakano Family Reunion
After the explosion, we return to Acadia for a last talk with DiMA. He is upset by the destruction of The Nucleus and realizes his peace efforts have failed. We move past his complaints and go downstairs to talk to Kasumi Nakano. With the truth out and the factions gone, Kasumi finally accepts she is not a synth and agrees to leave Acadia to rejoin her family in the Commonwealth.
With Kasumi ready to go, we head back to Far Harbor and take the Nakano family boat, leaving the island behind. When we reach the Commonwealth, we go to the Nakano home and see Kasumi reunite with her parents, Kenji and Rei. Talking to Kenji finishes the Far Harbor missing person quest, and he gives us a stash of hidden supplies as a reward. However, there is still more to do with the Acadia synths.
- Lore Fact: Kasumi Nakano’s belief that she was a synth was entirely psychological, stemming from her extreme isolation and her obsession with repairing pre-war technology. When killed, she does not drop a synth component, proving definitively that she was human the entire time.
The Brotherhood Assault on Acadia
Rather than letting the Acadia synths stay, we follow the Brotherhood of Steel’s strict anti-synth policy. We go to the Prydwen airship and report to Lancer Captain Kells about the hidden synth colony in Maine. Kells quickly approves a “Search and Destroy” mission and sends a strike team to eliminate the synths. We return to the island and meet Brotherhood Captain Larsen near the Acadia observatory to plan the final assault.
We enter the observatory with the Brotherhood strike team and fight our way through, defeating every synth inside, including DiMA and Faraday, using heavy energy weapons. After clearing the facility, we report back to Captain Larsen to finish the mission. With the Far Harbor threat gone, we get ready for our next goal: heading into the Glowing Sea to find the rogue scientist, Virgil.
- Lore Fact: The Brotherhood of Steel views all synthetic life as a severe, existential threat to humanity, fundamentally identical to the unchecked technology that caused the Great War. Their “Search and Destroy” protocol mandates the absolute eradication of any synth colony, regardless of whether the synths are peaceful or hostile.
