Set in the 1930s in a strict elite British boarding school called St Mathilda's, the story centres on a clique of girls who idolise their enigmatic diving instructor, Miss G, who had been a student at the same school where she now works. Di Radfield has a crush on Miss G, and is the firm favourite and ringleader of the girls who share her dormitory. When a beautiful and worldly wise Spanish girl named Fiamma Corona arrives at the school Miss G's focus is shifted away from the other girls. It becomes a triangle: Miss G becomes obsessed with Fiamma. Fiamma is disturbed by Miss G and also openly disgusted by her hypocrisies and deceptions, Di is terribly jealous and makes Fiamma's life hell.

Miss G (who claims to be a world traveller) goes to a nearby parochial town to buy some provisions. She draws the unwanted attention of some local lads and is visibly upset and in a near-panic when she returns to the school.

The bullying of Fiamma culminates in Di and her group frog marching her out of the school and telling her to go home. After unsuccessfully trying to phone for help and unable to return to Spain, Fiamma returns later that night.

Di and Fiamma begin to develop a friendship. Fiamma passes out after drinking alcohol at a dorm party, and Miss G takes her to her own room where she molests her while she is unconscious. Di witnesses this and flees.

The next morning, Fiamma is visibly upset, and Miss G is equally distressed as she runs around after her. Di is broody, and eventually lies to the rest of her gang that Fiamma seduced Miss G. Miss G realises her career may be over. She manipulates Di's affection for her into anger. She says that Fiamma will make up lies about her molesting her (even though it was true) and plans to get her kicked out of school.

Di's gang confront Fiamma and this turns ugly as Fiamma declines to answer Di's vicious questions, trying to explain what really happened. She hints at Miss G's lies and character defects. Fiamma runs into the forest as things become more violent as the girls catch up with her and, under Di's leadership, beat her with their sticks and fists. Fiamma has an asthma attack, and the girls stop, terrified. They run to get help, Di runs into Miss G (who had been watching the chase and beating with no attempt to stop it), who says she'll stay with Fiamma, and directs Di to go and get a teacher.

Miss G, now alone with Fiamma, refuses to give Fiamma her inhaler and calmly watches her die. Di returns to the scene first, just in time to see Miss G placing the inhaler in Fiamma's lifeless hand. As others arrive to help Miss G and Di stare at each other as Di realises what has just happened.

Later, Di tells the other girls that Miss G did not help Fiamma as she died, and, united, they confront Miss G. They are powerless to do anything, but they quit the diving team and symbolically turn in their sashes. The headmistress refuses to acknowledge the school's culpability, and is more concerned with the school's reputation. She releases Miss G from her duties temporarily.

The final scene has Di leaving the school to explore the world, as both Fiamma and Miss G had spoken of doing, whilst Miss G goes to the local village and finds a small room she can stay in. Miss G puts her few personal possessions on her bedside table. She puts one item there and then quickly removes it to make room for another item. After that, she counts the items to make sure that there are only five. This is reflects the school rule that only five personal items could be displayed on a night table at one time.^[8]

• Eva Green as Miss "G" Gribben, an institutionalised swimming and diving teacher who claims to be worldly wise but tells students adventure stories lifted from travel books as her own. She has difficulty in coping being outside of the school, even for local trips or inter school competitions.
• Juno Temple as Di Radfield
• Maria Valverde as Fiamma Coronna, a beautiful widely travelled and well read young Spanish aristocrat who is an excellent diver but is held back physically by asthma.
• Imogen Poots as Poppy
• Ellie Nunn as Lily
• Zoë Carroll as Rosie
• Adele McCann as Laurel
• Clemmie Dugdale as Fuzzy
• Sinéad Cusack as Miss Nieven
• Deirdre Donnelly as Miss Lacey

Cracks received a mixed reception from critics. It has a score of 45% on Rotten Tomatoes, based on 51 critic reviews. The site's critical consensus reads, "Atomospheric but not much else, Cracks is a formless film in search of compelling drama."^[9] On Metacritic, the film has a score of 54 out of 100 based on 12 critic reviews.^[5]

• The Prime of Miss Jean Brodie (novel)
• Notes on a Scandal

• Mellor, Richard (4 December 2009). "Cracks". Eye for Film.
• Millward, Liz; Dodd, Janice G.; Fubara-Manuel, Irene (2017). Killing Off the Lesbians: A Symbolic Annihilation on Film and Television. McFarland & Company. p. 28. ISBN 978-1476668161.
• Reed, Rex (15 March 2011). "Movie Review: Ridley Scott's Daughter Makes a Thrilling, Polarizing Debut With 'Cracks'". Observer.
• Snarker, Doroty (29 October 2009). ""Cracks" reveals a disturbing tale of boarding school obsession". AfterEllen.

• Official website
• Cracks at IMDb  
• Cracks at AllMovie
• Cracks at Box Office Mojo
• Cracks at Lumiere
• Cracks at Rotten Tomatoes