The Invisible Hand is about a boy, Sam, who has just started life at a boarding school and finds himself able to travel back in time to medieval Scotland. There he meets a girl, Leana, who can travel to the future, and the two of them become wrapped up in events in /Macbeth/, the Shakespeare play, and in the daily life of the school. The book is the first part of a series called Shakespeare's Moon. Each book is set in the same boarding school but focuses on a different Shakespeare play.