My Doomsday Fortress System

Seven days before the apocalypse, Anna binds with the Apocalypse Infrastructure System. She spends heavily, hoarding food and military supplies. When the world turns into a living hell, she transforms her bungalow into a steel-armored villa. Layered with defenses like a High-Voltage Grid and Heavy Machine Gun Turrets, she upgrades her base, enjoying a secure life in the desperate apocalypse.