When a zombie apocalypse shatters the world, a group of university seniors must fight to survive. Among them is Heeseung, strong, confident, and a natural leader, guiding his team through the chaos. But as they face dangers both undead and human, hidden tensions rise, and unexpected bonds begin to form. In the end, survival isn't just about the fight, it's about who they become when everything changes.

No one speaks to him. No one dares to. Locked away in the psychiatric hospital, Heeseung is a walking nightmare-silent, calculating, and burdened with a past that remains a mystery. The doctors whisper about him in hushed voices, and the nurses refuse to meet his gaze. No one knows what truly happened, but they know one thing: he is dangerous. Then comes the new psychologist, Sim Jake. Young, ambitious, and unaware of the unspoken rules, he takes the case no one else will. He wants to understand the man everyone fears. He wants to know the truth. But some mysteries are better left unsolved. Did he succeed in breaking through the criminal's silence? Or did he, too, become just another story whispered behind closed doors?

Amid moments of joy, laughter, and heartache, they must confront the realities of life, cherish the fleeting moments they share, and learn to support one another in ways they never expected.