1. Thomas and his friends are among the last survivors of a deadly disease that has killed most of the world's population. Thomas is beginning to lose his grip on reality and question whether his friends are even still alive.
2. Flashbacks show Thomas and his friend group before the disease, discussing plans to attend their high school prom.
3. One by one, Thomas imagines his friends dying from the disease, leaving him completely alone in the abandoned town. In his deteriorating mental state, he has trouble discerning reality.