Robin of Loxley is captured during the Crusades and is imprisoned at Khalil Prison in Jerusalem. With the help of fellow inmate Asneeze, who was arrested for jaywalking, he escapes and frees the other inmates. Robin is asked by Asneeze to find his son, Ahchoo. Upon returning to England, he finds Ahchoo and discovers that Prince John has assumed control while King Richard is away fighting in the Crusades. Unbeknownst to Richard, the prince is abusing his power. Robin returns to his family home, Loxley Hall, only to find it being repossessed by John's men. His family's blind servant, Blinkin, informs Robin that his family members and pets have all died as well, and the only thing his father left him is a key which opens "the greatest treasure in all the land."