We open with a voiceover from the protagonist, 2B:

Everything that lives is designed to end.

We are perpetually trapped in a never-ending spiral of life and death.

Is this a curse? Or some kind of punishment?

I often think about the god who blessed us with this cryptic puzzle… and wonder if we’ll ever have the chance to kill him.

A group of futuristic planes fly through a cloudy sky. We learn that this is the ‘YoRHa Squadron’, consisting of 7E, 12H, 2B, 11B, 4B and 1D. After some back-and-forth with their commanding officer, Operator 6O, telling us they’re after a ‘Goliath-class unit’, the YoRHa units start being shot down by a huge red laser beam. The survivors engage small round flying machines, first as planes and then transforming (naturally) into mecha. Before long, 2B is the only survivor.

2B flies into a narrow doorway in an enormous factory, and fights through numerous machine lifeforms. She bursts through a wall, trashing the flight unit, revealing herself to be an android in a black gothic lolita outfit (yeah…) fighting with a katana. 2B easily cuts her way through several waves of machines… only to be attacked by an enormous robot arm. The boss is named in the Celestial Alphabet, from which we can identify its name is Marx.

With some deft dodging, 2B seemingly defeats Marx… but at the last moment, Marx attacks again, only to be stopped by another android: 9S, who looks like a young boy, in his own flight unit. Supported by 9S, 2B makes her way through the factory, coldly rejecting 9S’s playful chatter. We learn a little: the androids are fighting the ‘machine lifeforms’, and 9S is essentially a recon unit.

After fighting through the factory, 2B finds herself confronted with the ‘Goliath-class’ unit she was seeking: an enormous, building-sized robot named Engels. Uncharacteristically, this machine talks, albeit only to say ‘kill… kill…’ Together, 2B and 9S fend off Engels’s waves of attacks and 2B ends up smashing Engels with its own arm. In the process, 9S is fatally damaged… and when two more Engels units appear out of the ocean, all saying ‘kill… kill…’, they agree that the only way they can win this battle is by detonating their ‘black boxes’, which causes an enormous explosion.

2B wakes up on the space station: it turns out 9S managed to upload her consciousness data at the last minute, but his own data was lost, so he has no memory of the fight.

We get a video explaining the situation. Humanity has been driven off Earth by invading aliens, and in particular, their army of ‘machine lifeforms’ who are adept at fighting any threat. The human survivors escaped to Earth’s moon, and from space, the android forces invaded in many waves, only to die at the last minute. “Glory to humanity!” the androids shout, saluting with a clenched fist.

After undergoing maintenance, 2B and 9S are dispatched to Earth with a new mission: liaise with the android Resistance, fighting an endless guerilla war against the machine lifeforms on Earth. In flight units, they descend to a ruined city, choked with vegetation, and make their way to the Resistance camp where they’re introduced to the leader, Anenome. She asks them to wipe out a dangerous incursion of machine lifeforms in the nearby desert.

But as 2B and 9S exterminate their way into the desert, the machines - oddly dressed in masks and carrying spears - seem more desperately afraid than terrifying enemies. (Players of the original NieR may recognise that the machines are dressed like the people of Facade). 9S insists that the machines’ utterances are meaningless, imitating humans without understanding, but as more and more machines speak of scary androids, we start to wonder.

The two reach an apartment complex, now choked with sand, as they pursue a fleeing machine deeper and deeper. Eventually, they come to a large cavity in the buildings, where machines are behaving very oddly: rocking baby carriages (“child. child. child.”), simulating sex (“my love. my love.”, “together forever. together forever.”) and certainly not behaving like weapons. The machine they were chasing appears, shouting “I’ll kill you for this!”, and the machines attack in a cacophany of dissonant statements - ‘I love you! Kill!’. Finally, as more machines emerge from all around, they settle into a chorus of one line:

“This cannot continue.”

Abruptly, the machines stop fighting, and clamber on top of each other to form a gigantic ball of machine bodies. The shell cracks open, and out falls… an android? A naked man with long white hair, who stands still until the androids attack. (The music here is great, turning ‘this cannot continue’ into the beat of the song.) The name: Adam.

As they fight, Adam displays more and more seemingly magic powers, weaving threads of light to attack and shield - but eventually, he is defeated as 2B and 9S stab him through with their swords. But from the body bursts out… another, identical naked man, who screams before escaping with the body of his brother. The androids flee, making their way out of the desert, and report the odd happenings back to command, who are equally befuddled.

We return to the Resistance camp for rest and maintenance. They return briefly to space, using a ‘transporter’ that sends their consciousness data up, then take on a new assignment… investigate the disappearance of YoRHa and Resistance androids in an old amusement park.

Arriving at the park, 2B and 9S find a group of peaceful machines, dressed in clown outfits and shooting not projectiles but balloons (“Oh! What fun!” “Let’s be happy together!”). Slowly, they make their way through the amusement park area, but no machines attack until they pass a machine warning them of danger, and ride on an old rollercoaster, and at last they have a few enemies to fight. Leaping off the coaster, they find themselves in a theatre… and suddenly a huge machine decorated with bodies of androids, built to resemble a woman in a long dress, attacks while singing.

This boss, named Simone, turns out to have taken over the minds and bodies of numerous androids, and attempts to hack 2B and 9S as well - but 9S hacks her back, allowing 2B to fight and defeat her. She says some strange things (all variations on “I must be beautiful!”), and even 9S starts to doubt… but we’ll get to that later on!

Outside the theatre, 2B and 9S abruptly run into a machine holding a white flag. The machine thanks them in much clearer English than the other machines have spoken, and leads them back through the carnival… and up into the treetops of a forested area. On their way, they see rockets carrying supplies up to the orbiting bases and the Moon. At the other end, they’re introduced to Pascal, who explains that this is a pacifist machine village that has been trading with Anenome. Though skeptical, they walk around the machine village and speak briefly to the various quirky machines in the village - notably Jean-Paul, who treats his fawning fans with utter disdain and is only admired the more for it, and the Big Sister Machine who asks them to find her sister in the desert after the smaller sister went looking for a spare part. Pascal, meanwhile, asks us to take a filter to Anenome to prove his good intentions.

On the way across the map, we encounter Father Servo, a strange machine resembling a stereotypical martial artist. We fight him, and he demands parts as payment for the ‘training’ - so that he might upgrade himself and give us a tougher fight later.