The new science teacher Dr. Julian Olcott (Carl Schell) with a mysterious past arrives in an institutional boarding school for troublemaker girls. Along the night, the intern Mary Smith (Mary McNeeran), who is blackmailing another teacher - Sir Alfred Whiteman (Maurice Marsac) - with some love letters, is slaughtered by a werewolf. The detective in charge of the investigation attributes the crime to a wolf, while her mate Priscilla (Barbara Lass) believes she was killed by Sir Alfred. On the next days, other deaths happen in the school, reducing the list of suspects.