First of all, I love the title. Taken from the song "You are my Sunshine", this book clearly looks at how "taking someone's sunshine away" can transform not only that person but everyone around.
The story takes place in Baton Rouge in the late 1980s and early 1990's when the narrator, who is telling his story many years later, is a young teenager. As young boys will, he worships Lindy, the girl who lives across the street to the point of stalking her. All of this seems like an innocent crush until the day in 1989 when is raped and her parents and the police come knocking on the door and identify the narrator as one of the suspects. Given he does not even really know what the word rape means at the time everyone loses interest in him as a suspect until his mother finds a box of the memorabilia about Lindy that he has stashed under his bed. Though she doesn't share the information with anyone other than his father, the fact that his mother could suspect him weighs on him.
The narrator makes another bad mistake - he tells everyone at school what happened to Lindy over the summer and she stops talking to him for a year. He spends the year changing his identity based on what he thinks she will like and thus losing many of his friends and prior interests.
The story also explores the other suspects in the crime - a 20 year old neighbour who has been up to no good since finishing high school, the adopted son of some truly creepy neighbours who doesn't seem to have any friends, and the most disturbing of all, this boy's adoptive father who is apparently a psychiatrist, but spends most of his time stalking a stray dog, taking pornographic pictures of his neighbours and abusing his wife, son and a string of foster children that come in and out of his house.
While the main storyline is this rape and the impact it has on the whole neighbourhood, the book also deals with the narrator's reaction to his parents' divorce, another tragedy that hits his family and his experimentation with girls, alcohol and drugs. There are also some interesting asides about life in Baton Rouge (especially how the heat affects it), and the impact of Hurricane Katrina, which directly hit only New Orleans, on that community.
By the end the mystery of the rape is solved by him (though apparently not the police) and we see how his life has turned out. We also see that Lindy eventually manages to move on though is obviously forever changed.