Daniel Redfern is an eleven-year-old, clarinet-playing, chubby kid who suffers all the usual growing pains: lashings of homework, bullies and a less-than-supportive best friend. And when he discovers a kid in his attic things get even more complicated. At first it seems like a big adventure-something to take his mind off everyday mundanities. The kid turns out to be a whiz at chemistry: a subject Daniel has especial difficulties with. But soon things take a more sinister turn with suited agents following him home from school, demanding to know the whereabouts of the boy in the attic, and Daniel soon finds himself torn between telling his parents and keeping the boy hidden. As time goes on the boy resists Daniel's attempts to work out who he is and, after a series of violent encounters, Daniel begins to think that the boy might be a threat to his family, and starts to wonder whether the secret's worth keeping at all.