This drama features countless plausible limited lifespans. All cast members are exposed to the danger of a limited lifespan. Therefore, this drama is hard to be boring and difficult to avoid pain and dilemmas. There are spectacular obstacles of virus infection-induced limited lifespans everywhere. Due to the indiscriminate attack, no one knows who will die in the next episode. Even the cast members themselves! Human time bombs ride the subway, eat instant ramen at convenience stores, and doze off in the Seoul Station waiting room. It's terrifying just to think about. However, the middle-aged woman sitting next to them doesn't know that fact. That's what's more terrifying. However, experts who know the terrifying power of the virus must engage in a blood-curdling chase. This drama is a drama version of the hide-and-seek game that humans instinctively like, which will be interesting to both the hiders and the seekers, and will make viewers sometimes become the hiders and sometimes the seekers, leaving them unable to move from the noose of tension every moment, every episode.