<P> Near the end of the journey, Azula attempts to flee the group, but experiences a hallucination of her mother . She tells the hallucination that thanks to Ozai, she has evidence that she can use to overthrow Zuko and become Fire Lord in his place, and intends to kill Ursa to prevent her interference . After she is restrained by Katara, the group is attacked by a giant wolf spirit . With the spirit overwhelming them, Azula convinces Zuko to free her, and lures it away with her lightning generation . That night, Zuko discovers that Azula's evidence is a letter from Ursa to Ikem, which claims that he is in fact Ikem's son . In the past, it is shown that Ozai had intercepted the letter after Ursa attempted to send it to Ikem . </P> <P> In the past, Ozai hires a Yuyan Archer named Vachir to kill Ikem . Returning to Ozai several months later after failing to complete his mission, Vachir tells him that Ikem fled into a nearby forest known for its violent plant and animal life, and is likely dead as a result . Confronting Ursa over both her communication with Ikem and her infidelity, Ozai states that he will allow Zuko to live despite his heritage, but claims to have had Ikem killed, much to Ursa's horror . </P> <P> In the present day, Azula discovers the disappearance of the letter and attacks Zuko, believing that Ursa told him to steal the letter from her . The two siblings fight until Azula realizes that, despite having the letter in his possession, Zuko hasn't taken the opportunity to destroy it . Zuko allows his sister to keep the letter . Entering Hira'a to ask for information on Ursa, Zuko and the others meet Noren and his wife Noriko, two members of the acting troupe that Ikem and Ursa were once part of . The couple say that following Ursa's engagement to Ozai, Ikem headed into Forgetful Valley, a forest in a canyon that heartbroken people supposedly travel to in order to forget their pasts and that when Ursa returned to Hira'a few years later, she travelled into Forgetful Valley as well . Noren and Noriko claim that no - one who has entered the valley has returned . Aang advises Zuko to forget about Ikem and destroy Ursa's letter, not wanting Zuko to lose his position as Fire Lord because of the new era he represents, but Zuko decides to travel to Forgetful Valley regardless . </P> <P> At this point, a second flashback reveals the full story behind Ursa's disappearance from the Fire Nation Capital . Ursa learnt from Azula that Ozai's father, Fire Lord Azulon, had ordered his son to kill Zuko as punishment for Ozai asking to be made heir to the throne, following the death of Iroh's son in the siege of Ba Sing Se . Discovering Ozai compliant with Azulon's demand, Ursa offered to provide him with an untraceable poison which he could use to kill Azulon and become Fire Lord in his place . Ozai agreed, on the condition that Ursa would leave the city and never return, lest she try to use the poison on him . As a second condition, Ozai forced Ursa to leave Azula and Zuko behind, in order to use them as collateral against her . </P>

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