When his father is arrested for printing a forbidden letter written by controversial reformer Martin Luther, twelve-year-old Storm escapes with the original. On the run from the authorities, Storm receives unexpected help from Maria, a young girl who lives in the city's underground tunnels. In a race against time, Storm tries to save his father from execution and to get Luther's letter into safe hands. But whom can he trust? What starts out as a fearful flight becomes a bold fight for freedom.