Opting to stay hidden inside a box within the ship, Kaina, Ririha and Yaona find themselves offloaded to the mobile fortress of Valghia. Now, they must somehow come up with a way to return to Atland, but Valghians are hot on their tails.

After saving an innocent girl from being executed, Kaina, Ririha and Yaona are given a small boat to escape. Unfortunately, without any means to navigate the boat accurately, they are unsure if they're heading in the right direction.

Just before the start of the war between Atland and Valghia, Kaina and his friends race to get proof of a great tree that can save everyone, including their enemies.

Drunk on power, the Admiral continues to operate the Builder and is determined to kill the King. Ririha tries to save her father, which results in making herself the Admiral's target. Will Kaina make it in time to save Ririha?