St. Mathilda's, the girls' boarding school in Cracks, is perched on a wind-strafed Lesbos off the British coast. In this atmospheric and broody melodrama set between the wars, Di Radfield (Juno Temple) is the alpha and pet of Miss G (Eva Green), a teacher sleek and chic as an art deco hood ornament.

Di, whose gimlet eyes calculate the precise rank of each girl in the St. Mathilda's social hierarchy, is too besotted with Miss G to notice that the teacher's tales of adventure sound a little off.

But then, everything at St. Mathilda's, where prisoners serve five-to-10-year sentences for being inconvenient, is a little off.

When Fiamma (Maria Valverde), a new student from Spain, arrives, she sees right through Miss G. Despite the girl's indifference, the teacher adopts her as her new pet, inciting Di's jealousy.

Director Jordan Scott (daughter of Sir Ridley)  captures the flash-fire heat of female rivalry and desire and the patchouli scent of cloistered girls trying to be worldly. But while Scott's movie has a consistent aura, it lacks a consistent tone. What are we to make of the movie, gauzy as a mist-shrouded lake and brutal as Lord of the Flies?

Contact movie critic Carrie Rickey at 215-854-5402 or crickey@phillynews.com. Read her blog, Flickgrrl, at http://www. philly.com/blogs/flickgrrl.