Atonement (2007)

In the summer of 1935, Briony (Soliz Ronan), a 13-year-old girl from a well-off British family, just began to try to write and has a rich imagination. One day, she secretly discovers that Robbie Turner (James McVoy), her servant's son, is having an affair with her sister Cecillia (Kate Knightley), and that he has written her an erotic love letter. Briony's rich imagination made up all kinds of terrible things. When her cousin Laura was raped, Briony was pretty sure she saw Robbie do it, and the testimony sent Robbie to prison, leaving a heartbroken Cecillia. World War II broke out, Robbie and Cecillia were both engaged in the fight to defend their country after they got out of prison, and Briony gave up going to Cambridge to become an army medical worker. No one can understand what she is doing, only she knows that she has great secrets and remorse. She plucked up the courage to unlock the secret so that she could truly atone for her sins and be forgiven. However, things changed beyond Briony's budget.