When Jeremy was just eight years old, his father passed away in an automobile accident. His family had been dreading this day almost all of his life, ever since a fortune-teller told him he would die at age forty. She was wrong: He died at age thirty-nine.

Five years later, one month before his thirteenth birthday, Jeremy gets a package in the mail that contains a locked, carved box and a note from his father. Fascinated by this gift, Jeremy and his lifelong best friend Lizzy are initially saddened to hear that the keys to the box were lost. Almost immediately, they become determined to find these keys and discover the meaning to life, something which the carving and the note both promise.

The search that follows is filled with ups and downs, tears and smiles, as Jeremy and Lizzie meet many strange and wonderful adults who attempt to help them unlock the box. Though Jeremy ultimately learns that some things are set up to happen in a certain way to aid him in his search, he embraces spontaneity a little bit as well. Throughout the story, he honors the memory of his father, as does his mother. She is still mourning the loss of her husband but is nevertheless a strong character who is a great means of support for her son. He is surprised when he realizes how much she needs him, too.