The fates of both Far Harbor and The Nucleus can be decided in the Cleansing the Land quest, as you uncover both the Wind Farm Kill Switch, and the Nuclear Launch Key.
However, you will get a unique Lever Action Rifle - Lucky Eddy - as well as a Perk that boosts damage at low health. If Acadia is raided, everyone inside will die - including Kasumi, which puts a damper on the end of the story. Similarly, if you tell Allen about DiMA's secret, you won't be able to stop the raid - but you can ask for Avery not to die. If you let DiMA make his case, you'll have the chance to plead for the rest of Acadia to be spared - but this will only happen if you've been helping the people of Far Harbor. If you convince DiMA to turn himself in, or tell Allen Lee, you'll trigger a potential raid on all of Acadia. Speaking with DiMA, you can forgive him and cover up his crime, or try to encourage him to turn himself in (or just do it anyway) If you help him, you'll gain a unique Synth Armor - Acadia's Shield - and start the path to the ending where peace can be achieved via the Reformation quest. After uncovering DiMA's secret medical facility in The Way Life Should Be quest, you'll have the opportunity to confront DiMA directly or go to Allen Lee with the evidence.
