see also: Prétear (manga)
A high school girl named Himeno Awayuki is attempting to adjust to her new life after her widowed father remarries wealthy widow Natsue. While taking a short cut to school, Himeno jumps out of a bush and lands on Hayate, the Knight of Wind. After some arguing Himeno wants to punch Hayate, but he blocks her hand causing a powerful light. Later she meets the other Leafé Knights who tell her that the red snow that has been falling on the town recently is being caused by the Princess of Disaster who is awakening, and that she is using Demon Larvae to absorb Leafé, the essence of all life. They ask Himeno to become the Prétear and help them protect the world. Himeno is initially reluctant, believing they are trying to play a trick on her. When a larva attacks them and begins stealing Leafé, Himeno agrees to help. Hayate tells her to take his hand and she merges with him to become the Prétear of Wind. After adjusting to her new powers, Himeno is able to defeat the larva.
As the series progresses, Himeno finds herself slowly falling in love with Hayate, who is initially cold and refuses to acknowledge her as the Prétear. Eventually she learns the Princess of Disaster was once a girl named Takako, who was the last Prétear. She had not enjoyed fighting, but did it anyway, also falling in love with Hayate. When he could not return her feelings, her anguish caused her powers to turn to evil, changing her into the Princess of Disaster.
Mawata, one of Himeno's stepsisters, has been overwhelmed with grief since the death of her father and holds herself distant from her family. She and Himeno temporarily connect over their shared feelings, but Mawata is hurt when she sees Himeno with Hayate. Mawata is in love with Sasame, but it is revealed that he was in love with Takako. He throws away his status as a Leafé Knight and joins Takako to become her Knight of Darkness. Takako uses Mawata's love for Sasame to hurt her even more, enabling Takako to use her to fuel the Great Tree of Fenrir.
The town is overrun by Great Tree of Fenrir. To protect the rest of her family, Himeno reveals her Prétear powers to them, then begs them to escape while she rescues Mawata. Instead, the family refuses to leave Mawata behind and put themselves in great physical danger to rescue her. Hayate and Sasame engage in a battle to the death, and Himeno climbs the Great Tree of Fenrir. Himeno's family starts attacking the bubble holding Mawata, calling to her desperately. Himeno continues up the tree to confront the Princess of Disaster. Mawata is freed and safe in the arms of her family. Takako doesn't want her to go and becomes desperate calling out for Sasame who appears after beating Hayate in battle. Fenrir asks Sasame to kill both Hayate and Himeno, but he is convinced by Himeno not to. Believing that not even Sasame loves her, Takako tries to kill herself, but Sasame shields her and dies. Takako comes back to her true self realizing that she loved Sasame too. Out of control, the tree captures Takako. Himeno tries to save her and she's attacked by the tree. Hayate shields her and then he dies in her arms.
To stop the tree, Himeno by herself becomes the legendary White Prétear and pours out a massive amount of Leafé. The town is restored, the Leafé Knights healed, and Sasame and Hayate are brought back to life. Hayate awakens to find the others crying over Himeno's lifeless body, lying in the grass as if she were sleeping. In agony, he holds her, then kisses her, which restores her life and enables her to awaken. At the end of the series, Himeno and Hayate are a couple, Himeno and her family are closer, Mawata is happier, and Takako is seen quietly sitting with Sasame.