The Sole Survivor has been thrust out into the harsh wastes, and sets off to find their home in Sanctuary Hills. Many secrets await their arrival in the now decrepit cul de sac, but will Shaun's presence be one of them?
This quest becomes available as soon as the Sole Survivor first escapes Vault 111, and comes across their home of Sanctuary Hills.
Upon arrival at Sanctuary Hills, the Sole Survivor will come across their old Mister Handy unit: Codsworth. Codsworth will offer to help search Sanctuary Hills with their owner, in an effort to find Shaun - the Sole Survivor’s kidnapped baby son.
Afterwards, the first requirement for this quest will be shown, in which the Sole Survivor and Codsworth will need to rid the neighborhood of its insect infestation.
After the insects have all been wiped out, and Shaun is seen to be nowhere in the vicinity, Codsworth will propose to the Sole Survivor that they investigate Concord, in which it will then warn them of the dangers of traveling there. Because of these established dangers, Codsworth will not be immediately available as a companion.
Exit Vault 111
While cryogenically frozen in Vault 111, I awoke just long enough to witness the murder of my wife/husband and the abduction of my infant son. I need to escape Vault 111 and return home, so I can begin to make sense of this tragedy.
I've made it out of Vault 111, only to find the world I knew completely destroyed by nuclear war. I need to head home, and see if there's anything left.
Talk to Codsworth
I've made it back to the old neighborhood. Surprisingly, Codsworth is still where I left him, and completely operational. I should talk with him, and see what he knows.
Search the Neighborhood with Codsworth
Codsworth suggests we search the old neighborhood for any sign of Shaun. It's as good a plan as any.
The search of the old neighborhood came up empty, so Codsworth suggested I continue looking in Concord, the next town over.
I haven't found Shaun yet, but I did meet a desparate man in need of help. What kind of world have I woken up to?
Enter the Museum
While the quest notes that the entire neighborhood must be purged of insects, there will frequently be more insects spawned than the kill quota accounts for.
Sanctuary Hills, the main location for this quest, will become available as a settlement.
While Codsworth will not immediately become a companion, it can be returned to later in the game, and it will join the Sole Survivor's party.