Sixteen-year-old Simon has always been considered odd. Three years ago, a skateboarding accident caused some minor brain damage and made him a little stranger. His career-driven parents mostly leave him alone, and he spends much of his time living in his imagination. When Sara, whom no one else can see, appears to Simon in class, he is fascinated by her and strikes up a friendship, even though he knows she may be pure hallucination, he's had imaginary friends before. Sara says she is there to 'help' him, but before the story ends, Simon discovers that it is he who needs to help Sara, not the other way around.