It all started with Kudou Kazuto crashing into something on his way back from work.  Overnight, the world has changed, and monsters now roam the surface of Earth...

YeZheng and Frank, alongside with other students from school, travel to the Mediterranean and the Bahamas for summer camp. As they ponder around the cruise, a sudden breakdown happens...  A story of romance and love, but at the same time the cruelty of survival...