The movie begins with the introduction that human longevity can now be extended over 100 years.
The main protagonist is Kathy, and follows her life from her childhood to adulthood. She reflects on her childhood at boarding school, Hailsham, where she makes friends with Tommy and Ruth. However, they later discover that the boarding school students are merely there to be organ donors for others. This information is revealed to them by Miss Emily, but she is later dismissed from her job due to this breach.
They now know of their fate but accept it. Kathy soon falls in love with Tommy, only to discover he is in love with Ruth. As the years go on, all three relocate to cottages – however, they are still expected to fulfill their role as donors.
Here they meet more people like themselves and discover that they are clones. However, they are informed that they can be removed from the organ donation list if they can prove that love exists between donors. Kathy becomes increasingly envious of Tommy and Ruth especially when their physical relationship begins. This leads to a break in the girls’ friendship. Kathy decides to leave to be a “carer” to those that have to give up their organs. Ruth and Tommy break up.
Years later, Kathy is still working as a carer. She later discovers that Ruth is very ill after having participated in two donations. Tommy is also very ill. Ruth reveals to Kathy that she only became involved in a relationship with Tommy because she was scared of being alone. She tells Kathy that if she proves she is in love she can escape from being made to give up her organs. She gives Kathy the address of the lady, Madame, who is in charge of these deferrals. Ruth dies soon after.
Kathy and Tommy begin their relationship and go to Hailsham, where the Madame and headmistress are. They inform them that there is no such thing as retrievals. Kathy and Tommy accept their fate and Tommy dies whilst being operated on. Kathy is left waiting to participate in her own donations.
