In the fifth year of the apocalypse, mutated beasts are rampant and human settlements are in danger. Lu Yan, a useless engineer, unexpectedly awakened the "Doomsday Fortress Sign-in System". He signed in at the abandoned factory and received the "First-order Alloy Wall Blueprint", and signed in at the Broken Supermarket and received the "Energy Rifle". While he collects supplies, kills mutant beasts and upgrades, he builds his own mechanical fortress, from protecting himself to accepting survivors. But as the fortress grows, he discovers that there is a conspiracy of alien civilization behind the apocalypse. Lu Yan will use the fortress as a shield and weapons as spears to lead mankind to fight a way out of the wasteland.
