Kyrie, Morte, and Taupy are headed to the continent of autumn leaves, and they manage to catch a ride with Agan. However, the World Salvation Committee of walruses returns again, only to find the World Destruction Committee aboard Agan's ship. The four eventually become captured inside the World Salvation Committee's submarine, however they soon find themselves submerging underwater. Naja and Rhi'a manage to board the submarine before it submerged. Naja reveals to the rest that Agan was smuggling a bomb aboard. Kyrie, Morte, and Taupy begin to defeat the submarine crew, while Naja and Rhi'a attempt to defuse the bomb. However, the bomb drops to the ground, thereby activating it. Everyone scurries away from the bomb, and the bomb explodes. This causes many leaks and damages throughout the submarine. Due to the massive flooding Morte, Naja, and Agan separate from Kyrie, Taupy, and Rhi'a in the control room and the bathroom, respectively. A plan is deducted to manually restart the engine, due to the unresponsive controls, and the only way to get there is through a small duct passage in the submarine. Taupy is guided to the engine room, but could not restart the engine, since there was a leak in the fuel tank. Agan reminisces of meeting a young man, later realized as Reve, a year ago, who tells Agan to send a message to Morte, saying that she must wait for him as he is trying to change the world. However, Agan never knew that the message was supposed to be sent to Morte until now. Hearing this, Morte is determined to know that there is enough fuel in the engine itself for the submarine to surface. They are able to surface and arrive on the continent. Naja and Rhi'a call a truce on the World Destruction Committee, and Agan is glad to finally have his message delivered to Morte.
キリエたち世界撲滅委員会は運び屋アガンのサンドシップに便乗して秋の大陸を目指していた。しかし、砂海の中を潜航していた世界救済委員会の潜砂艦が突如襲いかかり、アガンとともに世界撲滅委員会の三人も潜砂艦の中に連行されてしまう。逃走を試みるも、彼らのいる潜砂艦は深い砂海の底。果たして彼らの運命は!?
