Plot summary of Xenoblade Chronicles 3

This page describes a plot summary of Xenoblade Chronicles 3. It is not a full description nor a complete novelization, but simply an overview of major events.

Chapter 1: Ouroboros
A group of four kids dashes through a dense crowd awaiting the Queen's Anniversary. The clock strikes six, and time stops for all but one of the children. He looks up to see a planet in the sky, its shadow casting over the land.

In a starry abyss, two masses of energy meet. Across an unknown landscape, spherical chunks of terrain vanish in flashes of light. A battlefield comes into view, with footsoldiers and giant machines on both sides. Keves is the side wearing black and blue, while Agnus is in white and yellow. The battle is eventually won by Keves, and the Agnus machines are depleted and fall.

In this world, Aionios, killing the enemy faction empowers one's own with their life force. People are "born" as child soldiers, said to be from the Queen of the country, and know nothing but fight. They only live up to ten years (called "terms"), and those who survive that long are honoured in a Homecoming by the Queen as they fade away. The narrator, Noah, is an "off-seer", one who plays a flute melody to honour the dead (by battle or by Homecoming). He grew up in a friend group of himself, Lanz, Eunie, and Joran; today, he fights in a unit with Lanz, Eunie, Riku, and Mwamba. Since Noah likes to see off the enemy if their off-seer is dead, they tend to get left behind, and they must make the trek on foot back home yet again.

On arriving back to, the gang hits the showers. It's implied that Joran was killed shortly after a disagreement in the group's youth, and it's part of why Noah became an off-seer. The next day, a royal decree arrives and is visualised through the soldiers' Irises (essentially a modern-day smartphone and VR overlay in humans' eyes): a large mystery transport needs to be intercepted, and its ether cargo destroyed. The army deploys and advances through the Yzana Plains and into Alfeto Valley, killing the creatures that block their way and gaining minimal amounts of charge for the Flame Clocks in their eyes (much like those that power the colonies' giant machines). Mwamba talks about how his Homecoming is in a month, so he wants to transfer out of active service, and leaves the group to go on ahead.

The Keves army reaches the target first and begin to fire on a cloaked ship, with Agnus troops not far behind. The mystery ship loses cloak and makes a hard landing, deploying unmanned ground forces to protect itself as both sides approach while fighting each other, and the grey-wearing crew digs in to protect a glowing egg-shaped "Ouroboros Stone". The defenders are whittled down to just Guernica Vandham as the party approaches, who end up in a fight with three elite Agnus troops, including their own off-seer. The battle dies down and Noah becomes suspicious, so he stops fighting to kill and starts trying to talk, though he gets nowhere until Guernica interrupts the fight himself. He tries to tell the two groups who their "real enemy" is, but gets stabbed by a projectile from a new arrival: a giant humanoid monster with Mwamba in one hand and an Agnian, Hackt, in the other. The monster, which Guernica calls a Moebius, goads the soldiers to try and fight each other again by killing his captives. Guernica manages to get into the downed ship and fight the Moebius for a bit, but the ship is torn apart. All this only spurs the two groups of three soldiers into fighting the Moebius together. Guernica takes advantage of the distraction to open and activate the Ouroboros Stone, which causes Noah and the Agnian off-seer Mio to have an out-of-body experience and fuse together into a single larger form. The Moebius says they've used an Interlink to merge into an Ouroboros, which makes them his mortal enemies. After further fighting, the Moebius concedes defeat and leave, but not before projecting an infinity symbol into the sky, visible to many across the world. Noah and Mio return to normal and an uneasy truce forms. Guernica explains that all six of them are now Ouroboros, that he is sixty years old, that they must fight the Moebius coming after them, and that they must go to his City in Swordmarch to reclaim the proper way of things. He finally dies, and the two off-seers send him off. Noah and Mio use the fact that they shared memories to reduce the tensions between Lanz and Eunie, and Sena and Taion. They then make to return home.

Before reaching home, Noah, Lanz, Eunie, and Riku encounter Colony 9 troops that immediately open fire on them and ignore all else, so they are forced to return from where they came. Mio, Sena, Taion, and their tagalong Nopon Manana find similar trouble, and the groups end up meeting again at the site of Guernica's ship. Taion suspects the colony soldiers are under control of the Moebius due to their glowing red Irises, so Noah suggests they band together and go what Guernica told them, and Mio helps the others agree. They raid the ship's remnants for new clothes and other supplies. Mio notes in her diary that she has three months left.

A mystery girl arrives in the night and takes Guernica's eyepatch.

Chapter 2: Moebius
A flashback plays of an Agnian attack on the young Noah's group. They are rescued by a girl with two swords, Silvercoat Ethel, a legendary figure from Colony 4. Elsewhere, scenes of the Moebius attacking the party play in a theater. The lights go out as the Moebius walks onstage and breaks up into two people, "D" and another. D banters with another mysterious figure as others in similar getups, including P and H, are revealed and speak of controlling remote events. The presumed leader, Z, shuts them up. K is sent into action, and the meeting is adjourned.

It's the next morning. Lanz and Sena suspect they might be able to Interlink, but have no results yet. Taion is skeptical (since that would leave him with Eunie), while Noah thinks that it can only be done in the heat of the moment. The group begins to head south through Millick Meadows. Back in what is presumably Colony 4, Commander Ethel is receiving a new Consul, the K seen before. Consul K tells Ethel about the "deserters" and to take them down. The party has a slight disagreement at a fork in the road about whether to take the faster or safer path, and it's decided to take the safer path through Eagus Wilderness. Mio notices something odd about Noah's Blade, so he explains: When the group was young and training themselves, trying to decide what sort of weapon to use, Noah hated fighting so much he refused to use his Blade. When his non-Blade weapon broke after some bullying from Garvel, he visited Riku to get repairs. Riku instead offered Lucky Seven, a magic sword capable of slicing through anything, even a Ferronis, and convinced Noah to take it, hidden within the sword he uses normally.

The party is soon surprised by the arrival of Colony 4's Ferronis and Ethel. Noah tries to talk, but Ethel sees them as human-shaped black shadows, and is implied to be under the control of Consul K. During the ensuing fight, a patch of black fog rolls in, disrupting K's control of Ethel enough that he decides to step in personally. K turns into a Moebius and sucks up the life energy from both the Ferronis and its soldiers, healing him from any damage inflicted. Noah decides their only chance is to destroy the Ferronis's Flame Clock. In the chaos, Lanz and Sena manage to Interlink, as do Eunie and Taion. Noah uses Lucky Seven to destroy the Flame Clock, disabling the Ferronis and allowing them to defeat K, who reverts to human form. They take off his mask to find an old man's face, which quickly fades away as like a Homecoming. Noah plays for him even though everyone agrees he shouldn't, and Mio joins him.

The people of Colony 4 are all unharmed and freed of their personal Flame Clocks, and no longer see the party's Keves members are enemies. Ethel orders Bolearis and the others to accept the whole party despite half of them being Agnus. As the party rests, Taion notes that K seemed too similar to the Consuls of Agnus, which is very suspicious. The discussion afterward goes into whether the queens might be equally antagonistic, and whether all Consuls are Moebius.

The news of K's defeat reaches both queens. They both order more resources be put into exterminating the Ouroboros.