SABIKUI BISCO

Milo and Bisco head toward Touhoku in search of the legendary mushroom, Rust-Eater. After reuniting with their friend, the giant crab Actagawa, Milo struggles with his training to ride the crab, but ends up communicating with it thanks to his kindness. That night the two of them try to rest at the Nikkou War Memorial only to reunite with a jellyfish girl they met in Imihama.

On their way to Akita, Bisco and Milo pass by the sea of Calbero and arrive at a desolate town under threat from the deadly creatures, Flying Blowfish. A town that's also full of children and devoid of adults. Meanwhile, Pawoo encounters a mysterious couple living in some ruins as she pursues the others.

With the information obtained from Tetsujin Town, Bisco and Milo continue to head north. As they make their way through Shimobuki Prefecture, the land encased in snow, they encounter Tirol, nearly frozen to death. With Tirol's aid, the two continue their journey toward their final destination - Konakidani, the land said to contain the Rust Eater.

Bisco and Milo finally reach Konakidani when the Pipe Snake, a divine beast with two heads that's the size of a dragon, appears before them. That's also when Pawoo catches up to them with the worst possible timing. Soon enough, even Pawoo is dragged into the intense battle against the Pipe Snake. Meanwhile, Kurokawa also closes in around them...

Bisco is gravely wounded by the shot from Kurokawa. Milo leaves him behind to storm into enemy territory and rescue his captured friends, Pawoo and Jabi, but Kurokawa awaits with meticulously set traps. During their confrontation Kurokawa reveals his great ambition and the secret behind the Mushroom Keeper's persecution.

Bisco falls into Tetsujin's reactor, taking Kurokawa down with him. The reactor begins to overload, with Milo and the others just barely escaping in time as the dome starts to collapse. However, they're given no time to grieve their loss of Bisco before their next trial assails them. With Bisco gone, Milo tries to figure out what he can do on his own now.

The revived Testujin advances, destroying everything in its path. If this goes on Japan will once again be swallowed up by Rust... After inheriting the spirit of Bisco, Milo resolutely takes a stand against Testujin. Jabi, Pawoo, and Tirol race to his aid and they manage to corner the rampaging Testujin, but...

Tetsujin is heading for Imihama, repeatedly attacking Milo in a fierce assault. Yet just as he's about to be killed, Bisco revives from within Tetsujin. Together Bisco and Milo join forces in the final battle against Tetsujin!