Zuko's mother Ursa has been missing for years and Ozai is the only person who may know her whereabouts. Unable to extract the information from their father himself, Zuko releases Azula from the mental institution in the hopes that Ozai will entrust her with their mother's location. When Azula retrieves a letter hidden within one of Ozai's bunkers, Team Avatar agrees to travel with the royal siblings in order to help them find their mother. The content of the letter could be the key to Ursa's whereabouts, but it also holds a well kept secret that will give Zuko a whole new reason to find his long-lost mother.