Shinpi no hikari no umi

Sanso o gyōshuku suru aratana kyōi ga kaichū ni shutsugen. XIG no chīmu mārin ga kyōi ni taisho suru tame ni kaichū ni mukau naka, Hiroya wa, kono monsutā ga ningen ga tōki shita sangyō haiki-mono no sanbutsudearu koto o shirinagara gamu to taiji suru.

A new threat that condenses oxygen appears under the sea. As XIG's Team Marlin heads underneath the waves to deal with the threat, Hiroya confronts Gamu with the knowledge that this monster is a product of industrial waste dumped by humans.