Masquerade: Hell Academy
The quiet Numata Hiroshi is being blackmailed by his classmate, Himehara Yoritake, into performing sexual acts for him. One day, Himehara orders Numata to steal the exam answers off the teacher's desk, which sets off a chain of events culminating in the two men being among the captives taken by a criminal impersonating a police officer.
Their captor demands increasingly depraved acts from his hostages, and if they're going to survive, they have no choice but to comply...