The Fold Weapon is the ninth and final mission of Titanfall 2's single-player campaign.
After a short interrogation from Kuben Blisk and Slone, Jack is nearly executed in front of BT in order to coerce the Titan into handing over the Ark. BT instead destroys the room with his remaining combat capabilities, killing all the Grunts present but narrowly missing Blisk and Slone. Slone returns with her Titan and destroys BT's chassis.
Jack retrieves BT's SERE Kit and escapes the facility while simultaneously wreaking havoc with his smart pistol. Sarah Briggs deploys an empty Vanguard chassis to the battlefield, which Cooper places BT's memory core in. With the duo reunited, they set off to prevent the usage of the Fold Weapon.
They arrive at the Fold Weapon and are stopped by Slone. After a fight, they kill Slone and attempt to stop the Ark from being inputted into the Fold Weapon. BT is damaged when this attempt fails, and Blisk shows up to congratulate the duo on making it this far. He offers Jack a position in the Apex Predators before departing.
A damaged BT hurls himself in to the Ark and detonates his core to destroy it, but not before throwing Cooper out of the blast radius. Barker and Briggs rescue Cooper, and the Marauder Corps return to Harmony.