A pulse spread by cell phones erases brains of all who answered the phone. They turn extremely aggressive and murderous against each other and the "normies" - normal people who didn't pick up the call. Clay, a comic book artist, with a small group of "normies" travels through cataclysmically changed world in search for his son and wife, and eventually a dead zone without the cell phone signal.
A very bloody story full of gory details, not for the reader with a sensitive stomach. There's King's trademark suspense, although the book seems like an idea which gave way to lot of blood, but failed to fully develop into a story. A cross-breed between "The dawn of the dead" and "Happening", neither a movie I'd watch nor recommend.