Many Shonen Jump characters have big dreams, but this character's big dream is a nightmare! A very realistic reoccurring nightmare where a giant monster destroys a city. And it always ends with Ko, the poor dreamer, getting crushed under the rubble. But when Ko meets an unusual man who somehow knows about the monster in his dream, his nightmare takes on a whole new meaning.

A young boy in our ordinary world meets a girl battling a monster and becomes her servant... Why? And what will become of him? The story begins from there...