It starts with an itch you just can't shake. Then comes a fever and a tickle in your throat. A few days later, you'll be blabbing your secrets and chatting with strangers like they're old friends. Three more, and the paranoid hallucinations kick in.

And then you're dead.

When sixteen-year-old Kaelyn lets her best friend leave for school without saying goodbye, she never dreams that she might not see him again. Then a strange virus begins to sweep through her small island community, infecting young and old alike. As the dead pile up, the government quarantines the island: no one can leave, and no one can come back.

Cut off from the world, the remaining islanders must fend for themselves. Supplies are dwindling, fatalities rising, and panic is turning into violence. With no cure in sight, Kaelyn knows their only hope of survival is to band together. Desperate to save her home, she joins forces with a former rival and opens her heart to a boy she once feared.

But as the virus robs her of friends and family, Kaelyn realizes her efforts may be in vain. How can she fight an enemy that's too small to see?