From the Start, I Drew a Mystery Box, and the World Watched Me Perform

I woke up to find myself and ten billion people around the world dumped onto a post-apocalyptic train. At the start, each person got a beat-up blind box. I tapped mine without thinking and drew a daily sign-in System, with an SSS-rank skill, Time Rewind, as a bonus for my first sign-in. Before I could celebrate, screams came from the next car. I watched helplessly as Li Xinran, a calm and decisive girl, was dragged into the darkness by a monster. The comments flooded with sighs: “The heroine sacrificed at the start? Is that supposed to make her all-powerful?” I hit the rewind button, and time rolled back ten minutes. This time, I grabbed her wrist. “Don't open the door.” On this death train with no final destination, the only thing I can rely on is one random sign-in each day. Today, it's a pack of biscuits. Tomorrow, it might be the only way out of a desperate situation. This novel and its characters are entirely fictional. Any resemblance to real people or events is purely coincidental. Do not imitate.