It is England, 1935. Briony Tallis, 12 years old, decides to become a writer. Her first experiment in novelistic technique involves narrating from three different points of view an odd incident she witnesses from her bedroom window: her sister Cecilia undresses and steps into a fountain in the presence of Robbie Turner, the son of a family servant. Robbie has been educated at Cambridge under Mr. Tallis's patronage, and intends to become a physician. He and Cecilia are in love.

Briony's reconstruction of the incident is inaccurate, but she fails to recognize the lesson of her exercise in multiple perspectives: her version is sufficiently coherent for her to mistake it for reality. She jumps to further conclusions after she reads a letter that Robbie asks her to give to Cecilia and after witnessing a hot intimate moment between the two lovers in the library.

The last straw is Lola’s sexual assault in the gardens at night and Briony’s accusation of Robbie “the maniac”, who is wrongfully convicted and imprisoned for rape. All that also causes Cecilia's permanent estrangement from her family.

Briony

Robbie and Cecilia