What is the general plot line of Never Let Me Go?

This excellent novel opens in Hailsham, a school where three
friends, Kathy, Ruth and Tommy are introduced to us. Their lives at school are explored, with
many curious aspects to them that we do not understand, such as the revulsion that some
characters who visit the school show to the boys and girls. Kathy likes Tommy a great deal, but
at they grow up, it is Ruth and Tommy who form a relationship. They come to realise that they are
actually clones who have been created so that humans can harvest their organs. As they leave
school and ready themselves for what the future holds, they hear a rumour that if two clones are
really in love that they can gain a remittance from being harvested so that they can be together.
Kathy becomes a carer and Tommy and Ruth have their first donations. Ruth, before dying,
apologies to Tommy and Kathy for keeping them apart. Tommy and Kathy then try and find out what
they need to do to have time together, but they realises that this is a lie, and Tommy then dies
after a donation. The novel ends as Kathy looks forward to her own donations
beginning.