A brief investigation at the Nakano residence will tell the player that Kasumi believes herself to be a synth replacement, and that she's decided to leave her parents and travel to a place far north called Far Harbor to be with people like her. Arriving at the office, Ellie Perkins will tell Nick and the Sole Survivor to investigate the case of Kasumi Nakano - the missing daughter of a fisherman living beyond the northeast boundaries of the Commonwealth. The add-on starts off with the quest Far From Home when the player character listens to a radio message from the Valentine Detective Agency after completing the quest Getting a Clue, or when the player goes to the Nakano residence (possibly even before meeting Nick Valentine). This leads to the fighting between the Far Harbor citizens and the Children of Atom, but a greater plot involves a synth, who has ties with Nick Valentine. There, the Sole Survivor will search for a young woman, Kasumi Nakano, and a colony of synths. The add-on is set on Mount Desert Island, off the coast of Maine.
