When Shannon Hayes wakes from her morning nap to find her son eating his sister's intestines, the world goes straight to hell.

Her husband has gone missing, shambling corpses wander the streets, and a malevolent fog hangs over the bay, preventing anyone from leaving Queensport alive. Shannon flees to her husband's office building, where she meets Lily, a receptionist who carries a standard-issue handgun. Together, they confront creeping horrors and men driven to madness by a hostile creature who lurks beneath the sea. As they seek the truth of what happened to Shannon's family, her grasp on humanity stretches to the breaking point: how many innocent lives must be sacrificed to the watery abyss so that others might survive?

Shannon may never be the same again—if she wakes to see another day. Lily might be her best hope, and Lily only survived because she killed everyone else.