Kushima goes missing, and is later found without his cyberbrain. Brain death will occur within twelve hours, so Sota and Holon search for his cyberbrain while Haru searches the Metal for his consciousness. Meanwhile, with Kushima missing from the Trustee meeting, the Secretary-General has no choice but to approve Jeni En's motion to begin bringing the weather particle plants online.

With help from the Secretary-General, Sota deciphers the clues to bringing Kushima's cyberbrain back online, but instead of Kushima, an emergency AI awakens. The AI explains Kushima's suspicion that the weather particles cause the burning sea phenomenon, convincing the Secretary-General to halt weather particle production until Kushima can prove his theory. However, Jeni En temporarily revokes the Secretary-General's authority with a vote of no confidence.

After the spread of weather particles, drastic weather changes occur across the planet, and the burning sea phenomenon returns. Haru decides to use the experimental deep dive suit in an attempt to make contact with Kushima.

Haru makes contact with Eliza and receives Kushima's proof that the weather particles will cause worldwide disaster. Haru broadcasts the proof on the Metal, and the world's leaders quickly agree to shut down the Metal to kill the weather particle nanomachines. Kushima's consciousness then contacts Haru and explains that the ocean itself will replace the functionality of Metal via the salt water in the human body. Haru, restored to his younger self, is safely returned to the surface, where he reunites with Minamo.