A hundred years after the end of the nuclear war, the continents of the northern hemisphere were reduced to the "Rust Belt Wasteland" - the cracked surface was covered with metal debris, and deformed plants entangled the rusted ruins. Even more dangerous were the alien creatures called "singing insects": they looked like giant cockroaches, but they could devour steel and turn it into carapace.
Mechanic Lu Chen wanders around the wasteland with his homemade "iron shell" off-road vehicle, repairing old-era equipment in exchange for supplies. His left arm is a modified mechanical prosthesis that can dismantle parts and emit arcs. That day, when he was searching for the reactor in the ruins of "Gear Town", he ran into Su Ya, a former mercenary who was being hunted by a swarm of ringworms - she was carrying a crossbow that could fire shotgun shells, and hung a dagger ground from the carapace of ringworms. Behind her was a little boy clutching an old map.
The songbugs chasing Su Ya are particularly weird. Their carapace glows with blue light and they can spit out mucus that corrodes metal. On the verge of death, Lu Chen discovered that the weaknesses of these monsters were hidden in the gear-shaped organs in their abdomens - remnants of the "mechanical symbiosis" experiments of the old era. As more blue-light songbugs appeared, the two realized that this chase was no accident. The "Ark Base" marked on the map might hide the truth about the songbugs' mutation. What they didn't know was that deep in the base, there were even more terrifying "symbionts" waiting for their prey.
