A deadly disease has ravaged the United States, causing people to turn incorporeal before bursting into a shower of light.

When soft-spoken schoolteacher Florence is infected, the only thing left for her to do is atone for her biggest regret: her part in the death of her best friend.

With days left to live, she must cross a dystopian America to find her best friend's mother while being hunted by government agents tasked with controlling the spread of the disease.

But Florence's decision has dire consequences. Peter, her loving but overprotective boyfriend, refuses to leave her side, and every moment he spends with her puts him in danger of catching the disease or being executed for helping her.

As the miles add up, Florence must decide what she's willing to sacrifice for absolution.