Haru has become an official investigator and is asked to dive into the Metal to rescue the consciousness of an Artificial Island shareholder who has experienced braindown.

Holon collapses, and the others attempt to complete their investigation without her help.

Following the success of weather particle experimentation, the Secretary-General and Jeni En want to install weather particle plants as soon as possible. Kushima is opposed to the plan, suspecting that the weather particles will cause complications that threaten the Artificial Island. Meanwhile, Sota goes on a date with Holon.

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.