The following version of this book was used to create the guide: Yee, F.C. Avatar, The Last Airbender: The Shadow of Kyoshi. Amulet Books, 2020.

One year after she is discovered as the Avatar, Kyoshi travels the world subduing petty criminals and gang members and searching for her childhood friend, Yun. Yun was mistakenly misidentified as the Avatar and presumed killed by a spirit named Father Glowworm. Kyoshi's aid is requested by Fire Lord Zoryu of the Fire Nation, who explains that the Fire Nation is suffering from a famine and his mischevous older half-brother Chaejin is taking advantage of the tension to raise support for a coup and claim the throne for himself. She also reunites with her friend and lover Rangi. During a banquet at the royal palace, the group is attacked by Yun, who seeks revenge on everyone who ever lied to him about being the Avatar, including Rangi's mother Hei-Ran. Yun kills several palace guards before escaping, and Kyoshi realizes that that Father Glowworm has possessed him to do his bidding.

Kyoshi, Rangi, and Hei-Ran travel to North Chung-Ling to seek the counsel of Kuruk's former companion, Nyahitha. A water spirit, Nyahitha offers to aid Kyoshi in contacting Kuruk's spirit for advice against Father Glowworm. After calming a fiery confrontation between Zoryu's supporters and Chaejin's henchmen led by his mother Huazo, Nyahitha attempts to guide Kyoshi into the Spirit World, to little success. Kyoshi has continually struggled with the spiritual side of her role as the Avatar, a continued area of difficulty throughout the novel.

After the session, a message saying "Hail Fire Lord Chaejin" is burned into some local farmland, provoking a battle between Zoryu's and Chaejin's supporters. Yun takes advantage of the distraction to attack Hei-Ran, who barely survives after being stabbed by Yun when Kyoshi squanders an opportunity to pursue him in order to save her. Kyoshi deduces that Yun is working with Chaejin to undermine Zoryu in exchange for help in his crusade against his former mentors. Hei-Ran realizes that if a link between the two can be proven, Chaejin's coup will lose all legitimacy. Kyoshi sets out to do just this, desperate to keep the Fire Nation from falling into chaos.

Kyoshi captures Huazo and Chaejin and threatens to kill them unless they give up Yun, but Kuruk's spirit admonishes her and she realizes that the pair are not actually working with Yun. When she returns to the royal palace, she discovers that Zoryu has arrested an imposter of Yun and intends to execute him to stop the war before he proceeds to then purge Chaejin's entire clan. Kyoshi rescues the imposter, but Zoryu warns her that she must find the real Yun before his duplicity is revealed and a civil war breaks out.

Kyoshi travels to the ruins of an island charged with spiritual energy and finally communicates with Avatar Kuruk of the Northern Water Tribe. Kuruk shows her a memory of a confrontation with Father Glowworm, enabling her to track Yun, and reveals that although Yun has consumed Father Glowworm's powers, he is still in total control of his own actions. Kyoshi is taken aback.

Kyoshi pursues Yun to their childhood home, the estate of their deceased former mentor Jianzhu. Yun, now completely deranged and vengeful, swears to kill everyone who falsely worshipped him as the Avatar, leaving Kyoshi with no choice but to kill him. Aided by Rangi and her former companions in the Flying Opera Company, Kyoshi kills Yun in a decisive battle. In the aftermath, Zoryu plans to go through with his purge of Chaejin's clan, but is stopped by Kyoshi through her old friend Lao Ge.