What is the most interesting development in Ishiguro's Never Let Me Go? What is this story really about? I want something meaningful with substance.

Ishiguro's
novel is a futuristic work that explores the ethics of cloning.  In a
society that is so developed that it can create human clones to extend the lives of its citizen:
What rights should they have? How should they be viewed?  Suppose they are superior to the
humans whose lives they were created to prolong?

The novel's main characters
are first portrayed in...