In , Zuko is introduced as the main antagonist, who is attempting to capture Avatar Aang in hopes of reclaiming his honour. Throughout the season he pursues the Avatar, at times both helped and hindered by Iroh. Zuko competes in his quest against Zhao, an ambitious Fire Nation admiral who is also attempting to capture the Avatar for political gain. When Zhao captures Aang, Zuko disguises himself as "the Blue Spirit" and rescues Aang from Zhao's fortress to prevent him from accomplishing his goal. Later, Zuko escapes an assassination attempt plotted by Zhao. During the invasion of the Northern Water Tribe, Zuko captures Aang, but both nearly die in a snowstorm before they are rescued by Aang's friends. Zuko encounters Zhao and attacks him, but the Ocean Spirit abducts Zhao before the fight is concluded. Zuko attempts to save Zhao from the Ocean Spirit, but Zhao is too proud to accept Zuko's help. Zuko survives the battle with help from Iroh, who betrayed Zhao to protect the water spirits. In retaliation for Iroh's betrayal and Zuko's failure to capture the Avatar, Fire Lord Ozai assigns Zuko's younger sister Azula to capture Zuko and Iroh.