1) Kafka on the shore is about a young boy who runs away from home on a journey to find his mother and his sister. While he's out he may have fulfilled a prophecy told to his father; that his son would sleep with his mother and sister. Kafka finds himself while he has run away and learns more than he ever could have in school. But there is another story going on at the same time, the story of Nakata, an old man who has an uncanny ability to find lost cats due to the fact he can communicate with them. There are many characters through out the story who could be someone else which creates the magical realism genre along with other factors.
2) The theme of the story is that you cant escape whats meant to be. There's a lot of magical realism and suspension of disbelief in the story but the story remains modern at the same time. There are highly sexual tones used through out the novel as well.
3) We learn about the Oedipus prophecy that Kafka will have sexual relations with his mother and sister which is a major foreshadower of whats going to happen when he runs into two women that could possibly be his mother and sister. But at the same time do to the magical realism factor, there are many unexpected elements of the story that just pop up with no warning, like Cl. Sanders talking to Nakata.