Dragon Causes Disappearance of School Girls

by Len
(Singapore)

There is an 80's film about a school girl who disappears and her schoolmates suspect the headmaster of being involved.

Some of them discover a hidden passageway where they see the shadow of a dragon. In another scene, they see a dragon flying.

At one point, they touch the wall with a flower, and it opens up to the ominous passageway where girls are sacrificed.

I've searched for the title of this film over the years, but cannot find it. The closest plot belongs to The Girl with the Dragon Tattoo (2009). I always thought the title was something like 'Spirugyna'. Can anyone identify the movie?