Zuko and Azula grew up together as siblings under the care of their parents Ozai and Ursa. Zuko loves his sister very much and is very protective of her. Their lives were discrupted when they found out that there was a case of baby switching in the hospital on the day that Azula was born. They discovered that the real daughter was Katara, the poor, mean and resentful classmate of Azula. The lives of Azula and Katara are dramatically reversed in an instant. Azula wants to stay but Katara keeps pressuring her to leave. The weak-willed Azula decides to run away and stay with her hostile biological mother Kya and her good-for-nothing brother Sokka, Meanwhile, Zuko and his family decided to live at Europe.
Years later, Azula grows up to be a simple, beautiful and kind-hearted young lady. She works as a maid in a hotel resort. She meets a conceited and naughty hotel owner named Jet who gets smitten by Azula's charm and beauty. Jet does everything to get Azula's attention. He soon realizes that Azula is slowly changing him for the better. The guy proudly tells his best friend that he has found the woman he truly loves.
It turns out that Zuko is the best friend of Jet. Zuko returns from Europe to look for his beloved sister and after many years of separation, the "siblings" reunite. As Zuko and Azula get to know each other after so many years, they start to fall in love. Azula feels conflicted, because she is dating Jet. Zuko hides his emotions as he is preparing to be married to his long-time girlfriend, Mai. At this time, Azula will have Leukemia. The family and the villains of Azula are shocked because Azula has Leukemia and the anger of the villains Katara and Sokka changed into love for Azula.
Days later, Zuko and Azula finally get married and awhile after,Azula dies. Before Azula died, she wrote letters to her mothers(Kya & Ursa), her father, Zuko, Sokka and Katara. During her funeral, all of them read the letters Azula left them. In Azula's letter to her mothers, she states that she's lucky to have two loving mothers. In her father's letter, she states that she loves him very much and is the only father she Azula's letter to Katara & Sokka, she states that she's happy that they both loved her at , in Zuko's letter, she asks him to continue biking and always imagine that Azula is riding with him, and not to follow her in death.
Afterwards, Zuko asks Jet to deliver Azula's ashes to her favorite beach and asks that only him will do this and no one else. Jet asks Zuko if he's gonna go, but Zuko replies that he wants to say goodbye to her in his own way.
Afterwards, Zuko is biking on the road where he and Azula always went biking, but Zuko stops in the middle of the road and doesn't notice that there is truck coming and gets hit by the truck. After looking at the sky, Zuko says that he and Azula will be together again. Zuko dies afterwards.