Far From Home

Far from Home is a quest and achievement/trophy in the Fallout 4 add-on Far Harbor.

Quick walkthrough

 * Listen to Valentine's Detective Agency Radio
 * Talk to Ellie.
 * Travel to the Nakano Residence.
 * Talk to Kenji Nakano.
 * (Optional) Question Kenji and Rei Nakano.
 * Investigate the Boathouse.
 * Listen to Kasumi's holotape
 * Talk to Kenji.
 * Travel to Far Harbor.
 * Inform the Brotherhood of the Synth Refuge
 * Inform the Railroad of the Synth Refuge
 * Inform the Institute of the Synth Refuge

Detailed walkthrough
After completing Getting a Clue, a new radio station will appear on the Pip-Boy, Valentine's Detective Agency, with a message from Ellie Perkins to come and see her; a new case has arrived. Going to the agency has Ellie inform you of a new client, Kenji Nakano, the likelihood of it being a missing person case, and the man's seemingly uneasy attitude. Travel to the Nakano Residence, north of Coastal cottage. Meet with Kenji and his wife, Rei, whom informed the player character that their daughter, Kasumi, has gone missing, and want the Sole Survivor to help find her. Progressive questioning, beside some Charisma checks, leads the the player character to the boathouse, where a holotape, locked in an Expert safe, with the key inside a picture frame on a desk, reveals that Kasumi made contact with a colony of synths near a northern location called Far Harbor, and their presence made her question her own humanity, causing her to escape to find out the truth. Return to the Nakanos, and inform them of the discovery. Board the boat to Far Harbor, awarding the achievement on the spot.