In this thrilling prequel to the New York Times bestselling I Am Number series, the true reason for Number Five's betrayal will be revealed. Before joining the Mogadorians, infiltrating the Guard and committing a daring betrayal, the Fifth, like the others, went into hiding. But when his Chepan died, he is forced to survive on his own.  Wanting to finally get to know the world he had been avoiding, Five was soon confronted by the wrong people - the Mogadorians... In Five's Legacy, we learn how the one who was Lorien's last hope turned into one of the most dangerous opponents.