After a name was smashed off that person 's soul was returned and they were returned to the classroom ( Room 21 ) .
The surviving students realised that the curse could be undone by smashing a gravestone which bore the names of the students Killian had taken .
After a name was smashed off that person 's soul was returned and students were returned to the classroom ( Room 21 ) .
The surviving students realised that the curse could be undone by smashing a gravestone which bore the names of the students Killian had taken .