Out of Time

Out of Time is a main story quest in Fallout 4.

Detailed walkthrough
The player character, in the now dark vault room, vows to avenge their dead spouse (the spouse's wedding ring can be looted from their mummified corpse). They then wander around the Vault, discovering that most of its cryogenically suspended residents have died in their chambers as a result of a malfunction. Moving into the Vault's main hallways, they then discovers the skeletal remains of other Vault 111 residents and staff, suggesting that a violent confrontation took place. They also encounter a radroach within the Vault's power room, to their shock and disgust. Upon entering the living quarters and overseer's office, they soon discover the purpose of the vault, as well as the reason for all the skeletal remains--a mutiny had occurred in the vault, with Vault-Tec staff members rebelling against the Overseer. They can then hack into the Vault terminal or search for the password to open the entryway to the vault door chamber. Upon entering the exit chamber, they find a Pip-Boy 3000 Mark IV on the skeletal remains of a Vault-Tec scientist, which they promptly remove and connect to the vault door control system. The vault door opens and, as they enter the elevator, they are given one last opportunity to customize their appearance/stats before heading out into the wasteland of The Commonwealth.

Retrace the path the player character took to get to the vault to get back to the Sanctuary Hills. Codsworth will be near the player character's home.

Explore the neighborhood by following Codsworth who is searching for signs of life. This will lead to combat with Bloatflies and radroaches. When two battles are done, Codsworth will suggest the Sole Survivor go to Concord to continue the search for Shaun. It is possible to invite Codsworth to accompany as a companion.

The road to Concord leads south out of Sanctuary Hills across the bridge. On the way, there is a Red Rocket truck stop where a dog can be found that is willing to accompany the Sole Survivor as a companion. Upon reaching Concord this quest will complete and the next quest When Freedom Calls will begin.