Six months after vanishing into an underground silo with sixty-one others, Wynter and Chase emerge to an altered world. There is no sign of Noah and the rest of the group that was supposed to greet them when they surfaced--the same people Wynter was counting on to help her locate the antibiotics her gravely ill friend, Julie, needs.

As the clock ticks down on Julie's life, Wynter and Chase embark on a desperate search for medicine and answers. But what they find is not a nation on the cusp of recovery but one decimated by disease. What happened while they were underground?

With food and water in limited supply and their own survival in question, Chase and Wynter must venture further and further from the silo. They come face-to-face with a radically changed society, where communities scrabble to survive under rogue leaders and cities are war zones. As hope fades by the hour and Wynter learns the terrible truth of the last six months, she is called upon again to help save a nation she no longer recognizes--a place so chaotic she's no longer sure it can even survive.

With Tosca Lee's signature "beautifully written and deeply unnerving" (Jonathan Maberry, New York Times bestselling author) prose, A Single Light is a breathless thriller of nonstop suspense.