Fallout 4’s Plot Explained

The year is 2077. After World War 2, humanity focused most of its effort on harnessing atomic power, creating advanced technologies that were nothing short of unimaginable. However, this innovation sparked a century-long spike in global consumerism that caused mass resource shortages. The United States and China are on the verge of a nuclear war.

This is the basic timeline of Fallout 4, Bethesda’s second entry in the long-running Fallout franchise. Fallout 4 places much more emphasis on a character-driven story than previous Fallout entries, resulting in a lengthier main quest. If you can’t find the time to play Fallout 4 or need a refresher on its plot, read on.

Warning: this article contains spoilers for both the Fallout 4 main plot and the DLCs.Updated November 27, 2024, by Zackary Wiggs: Fallout 4 still stands as one of the major games of the Fallout series. Now with the TV show, all new fans are entering into the world of Fallout, and old fans may need a refresher into the post-apocalyptic ongoings of the sole survivor and their companions. No matter where or when you started your love of Fallout, Fallout 4 has plenty of twists and turns to keep you guessing. We’ve also included all of the DLC and the lore they provide.

How Fallout 4 Begins

While you’re preparing for a speech at a local Veteran’s Hall in Boston, a Vault-Tec salesman informs your family that they’ve been pre-selected into a local Vault thanks to your (or your husband’s) military service.

Moments later, a local news station announces that nuclear weapons are heading for American soil. Your family makes it into the local Vault 111 before the bombs fall. Vault-Tec places you and your family into cryo chambers without any consent, freezing the local inhabitants for an undetermined period of time.

At some point during your cryosleep, you and your significant other are thawed out. A mysterious bald man and two scientists appear and kidnap your child, Shaun. They murder your significant other in cold blood and refreeze you for an undetermined amount of time.

After Waking Up From Cryosleep

You wake up in a derelict Vault with no sign of human life. Your character successfully leaves the Vault, setting foot in the ruins of the Commonwealth for the first time since after the bombs fell. In a desperate attempt to find your son, you descend into the heart of Boston.

Along the way, you stumble across a group of people dressed in 18th-century colonial attire, fending off a pack of raiders. After you help them, the group introduces themselves as the Minutemen—a local faction that used to defend the locals until the group went defunct.

Their leader, Preston Garvey, gets your character up to speed with the state of the world. It turns out that you’ve been frozen for over 200 years. One of the Minutemen, Mama Murphy, has a vision about Shaun visiting Diamond City, a refuge built in the ruins of Fenway Park. She suggests you go there first.

You notice the sound of laser fire as you head further south. Closing in on the firefight reveals the Brotherhood of Steel, a group of technophiles that want nothing more than to exterminate the Institute—a faction that creates synthetic humans or ‘Synths’ that prey on the locals.

These Institute Synths look far more advanced than anything created before the Great War. Regardless of helping them, you continue to push through the ruins of Boston to reach Diamond City.

Looking For Your Son

Just outside of Diamond City, you come across a reporter named Piper arguing with who appears to be the mayor of the town. The city won’t let her back in. She cuts you a deal: let her interview you, and she’ll get you into Diamond City and help find Shaun. You accept.

Piper informs you that the town’s local detective, Nick Valentine, is the best in the business for locating missing people. It turns out it’s a common occurrence, as the Institute is infamous for kidnapping people. Unfortunately, Nick isn’t in his office. His assistant informs you that Nick’s being held captive in a nearby subway station. You set off to find Nick Valentine.

It turns out the thugs holding Nick hostage were residing in an underground Vault. You break into Vault 114 and find Nick Valentine. He’s a synth, much like the ones you saw the Brotherhood fighting, except Nick appears to be a much older model that is fully independent. You fight alongside Nick to escape and return to Diamond City.

Nick Valentine reveals that a child was escorted to Diamond City recently by a man named Conrad Kellogg, a mercenary known for taking shady jobs. You find a key to Kellogg’s home and find evidence of where he might be. With the help of Dogmeat, a dog you find just after leaving Sanctuary, you manage to track Kellogg down to a warehouse across Boston.

It’s in this warehouse that you find Kellogg. He looks exactly like the man who killed your spouse. It turns out he was working for the Institute, kidnapping your child under “the old man’s orders.”

You kill Kellogg and find a cybernetic component in his brain. Nick Valentine suggests using the cybernetic part in the Memory Den to access Kellogg’s memories, allowing them to find a way inside the Institute.

Finding The Institute

You and Nick Valentine make your way to the Memory Den. A local doctor creates a neural link between both of you and installs Kellogg’s cybernetic into Nick, allowing you to access Kellogg’s memories.

It turns out that Kellogg did escort a kid into his home, although they appear to be a few years older than when he was first taken. Kellogg was using his house as a safe place to teleport himself and Shaun into the Institute. There’s one person you could contact who might know how to create a teleportation device: a rogue Institute scientist named Virgil.

Virgil was last seen in the Glowing Sea, a radioactive ruin at the corner of Boston. You trek the wasteland to find the rogue Institute scientist.

This is often the first time the character enters the glowing sea, an area that is much more difficult than the rest of the Commonwealth.

He gives you the schematics for a teleporter and tells you that the teleport coordinates can be received from a destroyed Courser—a highly advanced and dangerous Synth. You hunt a Courser down and create the teleporter, giving you a clear path into the Institute.

You aren’t met with any resistance when you enter the facility. You find the kid from Kellogg’s vision, but it isn’t Shaun. An older gentleman named Father, seemingly the leader of the Institute, arrives and talks about how tough your journey must have been.

After a short conversation, you learn that the old man is Shaun. You were refrozen for 60 years after he was kidnapped, not ten. Shaun now leads the Institute in the pursuit of bettering humanity with Synths and other forms of advanced technology.

At this rate, You have seen the horrors of what Synths have done to the wasteland, but they now have the opportunity to work with the Institute alongside their son. You cannot convince Shaun to leave the Institute or change his ways, forcing you to align with one of the Commonwealth’s main factions: the Minutemen, Brotherhood of Steel, Institute, or Railroad.

How you feel about the Institute’s actions will determine the last third of Fallout 4’s story.

Siding With The Minutemen

• Objective: Recreate the Minutemen and destroy the Institute

Sturges will give you a holotape they can install in an Institute terminal, allowing Sturges to record the Institute’s teleportation sequence for later use. While he figures out a way to attack the Institute and end the Synth threat, you work alongside Preston Garvey to rebuild the Minutemen from the ground up.

He tasks you with claiming settlements across the Commonwealth under the Minutemen banner, promising to protect those people.

Many of the Minutemen quests follow the same routine, and there is no end to these “this area is under attack” quests.

Once you’ve claimed enough settlements, Preston will task you with taking over the Minutemen’s old HQ: The Castle. A veteran of the original Minutemen, Ronnie Shaw, helps you reclaim the HQ and get the Minutemen back to full strength.

Claiming eight or more settlements is enough to rebuild the Minutemen, allowing you to assault the Institute. Sturges finds a way into the Institute through the C.I.T. Ruins. The Minutemen enter the Institute through an old tunnel system and destroy the facility.

Siding With The Brotherhood Of Steel

• Objective: Eradicate all Synths by destroying the Institute.

For an attack on the Institute to work, the Brotherhood of Steel must be working at maximum efficiency. You’re sent out to rescue Paladin Danse’s platoon if they haven’t already done so, and they’ll need to take care of a few lesser issues the Brotherhood is facing.

Attacking the Institute is going to require some big guns. You’re tasked with getting Liberty Prime, a Pre War military robot, up and running. They convince a scientist, either Dr. Li or Professor Scara, to finish the project.

Dr. Li is the very same from the main plot of Fallout 3.

You scavenge some remaining parts for the war machine. Then you fight the Institute to take control of a beryllium agitator—the only power source that can get Liberty Prime back online.

With Liberty Prime ready, the only threat remaining is the Railroad. Synths cannot exist for the Commonwealth to remain safe in the Brotherhood’s eye, so you’re tasked with eliminating their main cell. Once they’re dealt with, the Brotherhood of Steel fights alongside you to destroy the Institute once and for all.

Siding With The Institute

• Objective: Eliminate the opposing factions of the Commonwealth.

To usher the Commonwealth into a new age of progress, the Institute must ensure its survival and get rid of its enemies. Shaun will task you with rescuing a few rogue Synths to start, most of which are at Bunker Hill.

This is mainly to gauge your loyalty to the Institute. Shaun invites you to a meeting shortly thereafter, wherein he reveals that he’s been battling cancer. Despite the Institute’s advanced technology, he can’t be cured. He wants you to take the role of Director once cancer takes his life.

With that meeting, the Institute’s main leaders are forced to trust you. Shaun asks you to begin Phase Three of the Institute’s plan. You’ll need to obtain a beryllium agitator in the Glowing Sea, a device that will generate enough power to keep the Institute running for the foreseeable future. After a short mission to improve the reactor, the Commonwealth is now ready to accept the Institute.

You make your way to Diamond City to announce that the Institute is real and will be protecting the Commonwealth. You work alongside the Institute to destroy the Brotherhood of Steel and Railroad to tie up loose ends. You spend your final moments with Shaun before he dies of terminal cancer, taking his mantle as the Institute’s Director.

Siding With The Railroad

• Objective: Give Synths complete freedom by destroying the Institute.

The Railroad is an underground agency sworn to protect Synths from the Institute. You work alongside the Railroad’s leader, Desdemona, and her crew to prepare the Institute’s Synths for an evacuation before the facility is permanently destroyed.

Before you can help the Railroad with this endeavor, you must first prove you’re worthy of being a Railroad Agent. Deacon, a key member of the Railroad, will assist you with a mission to reclaim an ex-Railroad HQ from Gen-1 Synths. Now that you have proven your mettle, Desdemona asks them to go undercover with the Institute to make contact with a rogue Synth named Liam.

Liam is able to make an escape plan for the Synths but needs time and assistance. Some major back and forth between Liam and the Railroad ensues, but the plan eventually falls into place.

Just before a proper attack can begin, one of the Institute’s rogue Synths catches wind that the Brotherhood of Steel is about to attack the Railroad’s HQ. You make your way back to HQ and help the Railroad defend against the upcoming attack.

In retaliation, the Railroad launches a counterattack on the Brotherhood’s Prydwen vessel. By placing charges aboard the ship, the Railroad manages to destroy the ship and force the Brotherhood out of Boston. The Railroad then initiates its attack on the Institute, evacuating all Synths before destroying the facility.

Fallout 4 Possible Endings

Fallout 4 has two main endings, one of which is exclusive to the Institute. The faction you choose that isn’t the Institute will determine post-ending dialogue and the faction that patrols the Commonwealth.

Nuclear Family (Institute Ending)

The Brotherhood of Steel and Railroad are eliminated, and the Minutemen never get the chance to develop. Institute Synths are deployed across the Commonwealth to patrol the streets. You and Shaun reminisce over lost time before Shaun dies of terminal cancer. You then become the Institute’s new Director.

Nuclear Option (Brotherhood, Minutemen, And Railroad Endings)

You—with the help of your aligned faction—destroy the Institute in a nuclear blast, leveling the C.I.T. Ruins. The Commonwealth no longer needs to fear Synths or the Institute.

The faction you have aligned with will slightly change the epilogue:

Fallout 4 DLC

There were a handful of DLC added on to Fallout 4 after release. Of them, Wasteland Workshop, Vault-Tec Workshop, and the Contraptions Workshop DLCs just add new items for your settlements and crafting.

However, the Automatron, Nuka-World, and Far Harbor DLCs add new areas, weapons, enemies, and new plots, extending your journey in the Commonwealth.

Automatron

Taking place on Fallout 4’s main map, as usual, you intercept a radio transmission that will lead you to the aftermath of a fight. There, you will find a handful of dead humans, destroyed robots, and the robot Ada.

After talking with Ada, it is revealed that the caravan of robotics specialists was attacked by a pack of robots led by The Mechanist.

The Mechanist—or the title of—is a reoccurring character that has also appeared in Fallout 3. A mantle that was once nothing more than a superhero character in pre-war radio shows.

Led by Ada, you learn how to modify and create robots at one of their settlements. After hunting down some of The Mechanist’s Robo-Brains and fighting the various Rust Devil raiders that scavenge robot parts, you are able to find The Mechanist’s lair located under the RobCo Sales and Service Center.

Upon confronting The Mechanist, you have the option of killing them or talking to them. If a conversation ensues, it is revealed that the Mechanist, whose real name is Isabel Cruz, took on the mantle of helping humans by creating robots. An order the robots mistook and chose to “save them” from the dangers of the Commonwealth by killing them all.

Nuka-World

You hear a radio broadcast that invites everyone to the amusement park Nuka-World. You can then travel to a tram station at the west of the map that will take them to Nuka-World proper.

There, you find the amusement park controlled by three different groups of raiders. You can enter the area by surviving a challenge, and defeating a boss raider, making a name for themselves.

Whether you side with The Pack, The Disciples, or The Operators makes little difference except for which of the groups you want to have control of the park and what kind of rewards you want from your missions.

The main plot is simple: you rise the ranks of the raiders, aligning with one of the groups, altering the balance of power, and choosing to wipe out one or more of the groups.

Far Harbor

A radio signal from the Nakano Residence will tell you to come visit the family. Upon arriving, you learn that the couple’s daughter, Kasumi has run off to Far Harbor off the coast of Maine. They ask you to please go find her, as she thinks she may be a synth and has gone there to join the synth colony.

Far Harbor itself is controlled by three different groups: the synths of Acadia on top of the island’s central mountain, the townsfolk of Far Harbor itself, and a group of the Children of Atom who have taken refuge in a nuclear submarine dock.

Exploring the island will give you each faction’s goals, including DiMA’s (the leader of the synths). You have the choice of siding with DiMA: unlocking their memories at the potential cost of hurting the Children of Atom but making the synths’ lives better.

You can also destroy the synths, making the townsfolk’s lives easier, or destroy the town via radiation at the behest of the Children. The hardest option is passing speech checks with DiMA and forging an alliance between all three factions.

You also have the option of contacting the BoS, having them invade the island and destroying Acadia, Or contacting the Institute and having them come to reclaim all the synths. Either option is only available if you haven’t completed the main questline and destroyed one of the factions.