It is part of the long running Black Emanuelle series of films starring Laura Gemser.

[1] Renouncing her sinful past, Emanuelle becomes a nun and moves into a convent, which also acts as an all-girl boarding school.

Sister Emanuelle is eventually sent to pick up new student Monika, the daughter of a rich Baron.

At the boarding school, the lecherous Monika freaks out after noticing that there does not seem to be any men around (execept for the old gardener) and tries to escape.

During a recreational trip to the nearby woods, Monika explores an old cottage and meets Rene, an armed criminal hiding there.

Discovering that Rene is armed and dangerous, Emanuelle decides to let their relationship continue, but convinces Anna that she is not sleeping with Monika.

While never revealing to Emanuelle the why to her lustful behavior, Monika does have an answer to why she is there: at her house, she seduced her stepmother.

Monika brings Anna to the tower, and the two spy on Emanuelle unwillingly having sex with Rene.

Emanuelle eventually figures out that Monika lied to her, but before she can react, the gardener enters the tower with a shotgun, believing robbers have broken into the building.

Shocked, the nuns and girls quietly watch Emanuelle leave the convent in her civilian clothes.