A high school class, containing 32 students, all receive a strange text message on their cell phones one night. It welcomes them to the "Ousama Game," in which they are given specific tasks to carry out in a 24 hour period.

No one takes it very seriously at first, as the tasks are trivial things like having one student kiss another. Soon, the tasks escalate beyond what the kids are willing to do, and they learn that the cost of failure is death. Will they be able to find a way out of the Ousama Game before more people die, and the living lose their integrity and humanity through their participation in the increasingly horrible daily tasks?

(Source: MangaHelpers)