Upon waking up at school, a boy simply referred to as Senpai finds that the world has been transformed in a bizarre way. All the other students are unconscious, and strange sheep are scattered throughout the campus. The only other person awake is Romi Sawada, a fellow student who possesses magical powers and has grown sheep horns. The girl seems to have control over the mysterious sheep that roam about and explains to Senpai that he was under a sleeping spell. With the two of them being the only ones awake, Senpai and Sawada spend their time goofing around.

While the rest of society is left to slumber, the pair freely do as they please while enjoying each other's company. However, the outside world is in chaos with monsters wandering around that can only be kept at bay by Sawada's magic. As these ominous threats loom closer, the teenagers' peaceful refuge may not last long.