Though I originally thought this was a horror drama, this is more like a murder mystery surrounding the unexplained deaths of a few students. These deaths were triggered by an eerie ringtone that signifies a missed call. The phone message is a recording of the few seconds before the person dies, screams and all.
Enter Detective Sendo and Yumi, a sci-fi magazine writer/employee. They pair up to find out what is causing the murders and how they can prevent it from happening.
The body count is high in this drama and there are lots of cheap scares that reminded me of Ringu and my fear of long-haired Japanese girls (heh). And just when you think the mystery is solved, many other twists come your way.