The Hero and the Crown by Robin McKinley is the prequel to McKinley's bestselling novel The Blue Sword. In The Hero and the Crown, Aerin-sol grows up in the home of her father, the King of Damar, feeling as though she has never really belonged because of the belief that her mother was a witch from the North. Due to this, Aerin feels as though she has something to prove. Aerin begins slaying dragons after reading an ancient book about the creatures, eventually killing the huge menace known as Maur, the Black Dragon. This battle leaves Aerin badly injured, leading her to follow a dream that takes her to the home of the mysterious Luthe who will finally give Aerin the answers she needs and send her into a final battle that will change her life forever. The Hero and the Crown is a novel of self discovery, of family and country, that will inspire as well as entertain.

Aerin-sol, daughter of the King of Damar, has always felt as if she does not belong in the house of Arlbeth. This feeling is underscored by the taunting of Aerin's cousin, Galanna. Galanna dislikes Aerin, in part because she has always wanted to marry the first sola, the first in line for the crown, but Tor-sola is clearly in love with Aerin. Galanna is forced to marry the second sola, Perlith, a man with an acid tongue as cutting as Galanna's. Galanna's behavior has been so bad in the past that she bullied Aerin into eating a whole branch of surka, a plant known to be fatal to all but those with royal blood. Aerin is sick for months afterward. During her slow recovery, Aerin reads a history of Damar that talks about the huge dragons that once roamed the countryside and gives a recipe for an ointment said to be able to resist the fire of dragons.

During her long recovery from the surka, Aerin befriends her father's injured warhorse, a huge white stallion whose hind leg was rendered useless by a sword wound. Slowly, day by day, Aerin gains the trust of this horse, Talat. In time, Aerin is able to ride Talat despite his injury. In fact, Aerin takes Talat's tackle and modifies it to create a unique saddle that allows Aerin to control the horses movements through the pressure of her small legs. Also during this time, Aerin begins to work with herbs to recreate the ointment mentioned in the ancient history on dragons. Eventually Aerin finds a combination that creates an ointment that does in fact protect the wearer from fire.

Soon after her recovery is complete, Aerin is having breakfast with her father when a man from a nearby village comes to ask for the King's help in riding his village of a dragon. Aerin sees this as her chance to prove her ointment works. Aerin sneaks off on Talat and goes to the village, slaying the dragon and his mate. On the way out, Aerin runs into the men her father sent to slay the dragons. These men take Aerin back to her father's house and show him the proof of her actions. Aerin explains all that she has learned and done to her father. Arlbeth is so impressed with his daughter that he presents her with her own sword, swearing her to his service from that moment on. Arlbeth sends Aerin out to slay many dragons in the months after her first experience, making in her a hero of the people.

Trouble begins to grow in the west when a baron there becomes infected with demon-mischief. Arlbeth and Tor must ride out to stop the trouble. On the day they are to leave, a messenger comes and tells them that Maur, the Black Dragon, has awaken and is tormenting his village. Arlbeth takes this news as sign of dark days of battle ahead, riding out to the west anyway. Aerin decides to ride to the village's rescue and slay the dragon. Maur is much larger and a much stronger enemy than Aerin believed, however. Maur's fire breath burns through the ointment she wears and burns her arm and face, leaving her lungs badly damaged. However, Aerin manages to hang on and kill the beast despite her injuries.

Aerin lies in the valley below Maur's nest for a long time, slowly recovering from her injuries. When she is well enough, Aerin goes to inspect the dead dragon and finds a red jewel under its body. Aerin keeps the jewel, believing it might serve a purpose one day. Finally Aerin knows she must return home if she is to survive her injuries. On the road, Aerin comes across Arlbeth and Tor who have come looking for her. They help Aerin return home where the head of Maur has been brought to celebrate Aerin's victory. However, Aerin struggles still with her injuries, hearing in her mind the taunting of Maur and dreaming of a mysterious blond haired man who calls for her to come find him.

One night, Aerin slips out of the castle and rides into the North where she finds the mysterious blond man, Luthe. Luthe makes Aerin drink from a nearby river that proves to have mystical properties. Aerin quickly regains her health. Luthe tells Aerin that he once knew her mother, sharing with her information on her mother that no one else could have shared. Luthe then tells Aerin that the trouble that has been plaguing her country comes from her own uncle, Agsded. Luthe tells Aerin that if she does not face Agsded, and defeat him, that her country will be destroyed.

Aerin rides out into the North and is quickly joined by a group of cat-like animals known as folstza and the dog-like creatures called yerig. Aerin also has the support of a sword Luthe has given her known as Gonturan. Aerin arrives at a tower in the North and the animals help find a way inside. Aerin climbs for what seems like days until she finally finds a man who wears a face eerily like her own. This man wears a crown that has been missing from Damar for centuries known as the Hero's crown. This crown makes him nearly invincible against Aerin's sword. However, when Aerin throws a surka wreath containing the jewel she found under Maur's body, Agsded is destroyed. Aerin falls a great distance and finds herself in a world many generations in the future.

Luthe meets Aerin on the road as she returns, telling her how he had to use his magic to bring her back to her present time. Aerin and Luthe become lovers, sharing the secret that they are both more than mortal. Luthe then urges Aerin to return to Damar, assuring her they will be together again. As Aerin approaches the city where she grew up, she discovers it under siege by an army from the North. Aerin fights alongside Tor, to whom she has given the Hero's crown. Together they beat back the army, ending the siege. However, the city is still struggling under a cloud of despair that is only increased with the knowledge that Arlbeth has died. Aerin recalls the head of Maur and knows it must be removed from the castle. Together, Aerin and Tor roll the massive head out of the city where it lands on the field of battle, turning it into a desert. The sense of despair is lifted. In the days after the battle, Aerin and Tor are married, together ruling the country of Damar.