Escape from HellSchool

Cally Hart is a High School student and Louise Hart her young brother, at the Grade School student they both study at a Private school (built 1889)
Cally loved to loiter around the campus with her brother every after class in the afternoon.
But one afternoon, they found themselves lost in a loop inside the campus' other realm.
Pictures moving, black unknown figures, hands sprouting from walls then throwing axes on them, steep stairs without railings, spike traps trapdoors, moving statues and statuettes. All living things seems trying to kill them for some reason. Through the siblings frightful adventure in the school's other realm they met Cally's classmate also a close friend, Lucien.
Will they all escape in the chasm of the campus namely the HellSchool.