Like the original manga, the new series centers on Naraka High School, a school that only admits students who can see an island in the sky. While it is allegedly a prestige school where graduates are guaranteed to get excellent government jobs, the students are forced to fight for survival in order to graduate.

The new main character is Hiroshi, a 15-year-old boy who can see the island in the sky. He and his friends enter Naraka High School as a test of courage but only he alone returns.