Olive's Ocean is a good book because of the plot.Olive is a girl who wants to be friends with Martha Boyle. She says so in her diary. But Olive dies in a car accident before she can tell Martha. Olive's mom finds the diary and gives Martha the page with her name on it. After she sees the page, Martha goes on a vacation to her grandmother's house. While she's there, she sees a boy named Jimmy Manning, her old rival. While she sees him there she begins to like him, more and more each day.
Martha begins to wonder if she should tell anyone about the paper that Olive's mom gave her, but she never does tell anyone. For the whole summer, she thinks about Olive. She couldn't change what happened, but she thought she could make things better. Olive always wanted to go to the ocean, but she couldn't go, so Martha brought a jar of ocean back home for Olive's mother. Olive also wanted to be a writer, so Martha wrote a novel based on Olive. So she tried to make Olive's dreams come true.
In the end, Martha rides home and brings the jar of water, and writes the beginning of her novel. But Olive's mother doesn't live in the same place when she arrives home. But even though Martha couldn't give the water to Olive's mom, she still did a nice thing by thinking about someone else. And Olive's diary helped Martha decide what she wanted to be when she grew up.