Warning: Spoilers ahead.
Following Rust-Eater Bisco - Episode 10
, this ep begins with Chiroru
chasing after Tetsujin
in a red truck. Their first stop is Shimobuki Base so Pawoo can meet up with her subordinates. Chiroru conveniently found a manual on operation Tetsujin at the base.
Then we see Milo, Actagawa and Jabi. They survived their fall off the cliff. Of course, they did! They can’t kill off Milo, too! There would be no main characters left!
While Milo treats Jabi’s wounded leg, the two theorize about what this Tetsujin is. With its Rust power, it seems to be a god of death. Since Rust Eater is the antithesis, the Rust Eater is like a death god eater.
Milo leaves Jabi to be taken care of by the nomad people while he goes after Tetsujin, who is headed for Imihama. Jabi tells him not to die. And even calls him Bisco, as he believe Bisco’s soul passed on to Milo.
Meanwhile, some nomads attack Tetsujin/Kurokawa with missiles but get wasted by its rust.
Tetsujin keeps moving toward Imihama. Its next stop is Nuts’ village, Calvero! The kids see it coming and realize it will likely mean the destruction of their village. They don’t like but, but Kousuke points out that they have no choice but to evacuate.
So all the kids run away from the village as fast as they can, but of course Tetsujin is huge and catches up to them quickly. Tetsujin sets off a blast trip left behind by the kids, and that pisses it off.
Nuts decides to be a decoy to let the others escape. He even throws his harpoon at Tetsujin! Which of course has no effect.
Right as Nuts is about to be blasted to death, an arrow comes out of nowhere and produces a protective mushroom around him and shields him.
Milo shows his face to Tetsujin and starts talking like Bisco again. The kids can tell Milo is different than before.
Milo engages in a mushroom arrow/blast fight with Tetsujin. Then Pawoo drops out of the air thanks to one of those slug planes. She whacks Tetsujin in the head. Chiroru and Jabi meet up with Milo in the red truck.
The Imihama Watch take care of the kids, while the military again hits Tetsujin with ineffective firepower.
Back at Imihama, the prostitutes and the Madam catch a video of Tetsujin on its way. Although who’s recording this on camera is never explained. It’s just convenient.
Tetsujin gets tired of getting bombarded by multiple enemies and opens its chest cavity, releasing another powerful rust blast that kills off a bunch of planes and tanks. Milo’s group barely survives the rust windstorm, thanks to Actagawa’s protection.
Despite Jabi’s warnings, Milo injects himself with Bishamon poison to give him a strength boost. His body won’t last long after taking it.
The people of Imihama see Milo face down Tetsujin. Milo uses mushrooms to jump onto Tetsujin’s back and starts cutting and stabbing away at the monster. He happens to find Bisco’s goggles lodged in Tetsujin. Then, somehow, a fully healed (alive) Bisco claws its way out of Tetsujin! He’s back! What?!