Maggie copes with her fears and anxiety by collecting things that remind her of people and storing them in boxes around her room. Her attachment is obsessive and she became angry and upset when she feels that someone has gotten into her boxes. By the time her habit is discovered, it has become a serious issue. Her supportive family enlists the help of a child psychologist who helps Maggie work through her fears. In the end, Maggie learns to let go and accept that not everyone stays, but memories are forever.
As a side not, Maggie has a very interesting hobby -- trap shooting -- which you don't find often in children's books. It's terribly well integrated into the rest of the story, but it was obviously too good to leave out!
I enjoyed this sweet and affirming look at the issue of hoarding. Maggie is resourceful and thoughtful, explaining reasonably articulately what her thought process is and why it is so hard for her to let go of her treasures. The author does a good job of showing the gradual healing process of Maggie working through her issues. The family is a bit too perfect for my tastes, but that reduces distractions and allows the book to focus on Maggie. The loss of a favorite pet towards the end helps push Maggie to a full understanding of acceptance, but an ethical dilemma at a shooting tournament in the conclusion seemed a bit less vital to the story.