Doomsday Cold Wave: I Have a Mobile Fortress, Who Can I Fear?

Before the extreme cold of the apocalypse arrives, I stockpiled enough supplies for 10 years and hid in an underground cave, soaking in hot springs. Soon, the temperature plummeted to -70°C, and under the night sky, fierce winds and blizzards engulfed everything. Meanwhile, my treacherous boyfriend's train encounters the icy end of the world.