A Heart So Fierce And Broken begins with grey which; in the first book found out that he is the secret heir of ember fall, so he went into hiding as not to get recognized and keep the kingdom safe.
Prince Rhen is no longer under a curse, but he still has many hardships to face, including the rumors of another heir that is coming in between his coronation; though he does have Harper by his side, he is still down a powerful ally since his guard commander grey had disappeared and thought dead.
After the last book’s events, Grey had stayed a few days at his mother’s house to heal, but he quickly left since it could prove very dangerous for her and him, so he hid as a man called Hawk, and he works for a person named Warwick.
There, he made friends with his partner, and Grey teaches him swordsmanship, but he soon realized that the crown prince is looking for Grey and that grey has magic but cannot yet use it, but Tycho decides to keep it a secret despite the reward that has been put up.
Meanwhile, Karis Lauran from Syhl shallow is moving towards the castle with her two daughters, the older one being Lia Mara, who is intelligent and ultimately wants peace for both of the kingdoms; meanwhile the younger one, Nola Verin is the heir to the throne for their kingdom and is just as ruthless like their mother and they are going to ember fall hoping for an alliance in the form of marriage among prince Rhen and the younger daughter Nola Verin.
The party from Syhl shallow arrives at the castle, and they propose the offering. Still, Rhen already knows of the cruelty of Karis Luran and how she had killed thousands of his people, and he immediately denies which forces them to go back with nothing.
Lia Mara wanted things to go peacefully and not all-out war, so while they were camping for the night, she sneaks back to the castle with her two personal guards and tries to reason with him, but Rhen cannot afford to trust Karis Luran, so he takes her and locks her in a room.
Grey, who was readying the field for a fighting match, was taken inside quietly by one of their contestants and he turned out to be injured. Still, he had to get the money today for his family so Grey goes into the field pretending to be him instead. Still, it turns out to be a mistake since his first challenger was the new guard commander that grey had thought himself, so he gets recognized and tries to run away, but that just gets him caught since even though he has been missing for months, no one knows that he is the heir so he could have gotten away with it. Still, he ran, and it made him seem suspicious, but to make it worse, Tycho runs after them to attack, and they take him too.
Lia Mara was trying to escape from her room when she saw Grey being brought in front of prince Rhen, and she figures out that he is the heir and he is the one everyone is looking for.
Grey doesn’t tell anything Rhen, and in the end, the prince gives Grey a day to consider and lets him stay in one of the rooms for the time being.
Lia Mara was in the next room, so using the fireplace, she could cross to Grey’s room which she did, and she gave him the proposal of being allies with her mother, but then again, he denies.
At the end of the promised day, they take grey to torture him, but they know that it would be nothing to make him tell the truth. Hence, they brought Tycho to torture him too, but grey uses his magic which he does not have control over, and he somehow manages to knock out everyone in the room there, including prince Rhen.
Grey and Tycho escape with the help of the healer Noah and Harper’s brother Jake who do it because of Harper and because they got a promise by Grey that he will send them back home as soon as he can, and even Lia Mara escapes.
Grey, Tycho, Jake, and Noah stay at an inn for a night, but it’s too dangerous, and in the morning, Harper comes to see. Later, they eventually decide the only place they have left to go is Syhl shallow with the help of Lia Mara who promises that they will be safe since Rhen must have figured out that Grey is the heir and the one with magic.
They all start moving on foot. They get too tired and decide to rest for a while since they have also eaten nothing, and they are starving.
Then out of nowhere, a scraper named Lisak flies out of the sky, a magical creature saved from his cage by Grey, and he wants to ally with them since they can also help him return to his home and the queen Karis Luran has something he wants. Still, the Scraver also comes useful since he also gets grey to heal himself and says he could teach him more so eventually he can also heal Tycho and the Scraver can also fly, which would come in useful for them to look ahead. He could catch a goose from the sky for them to eat, so they let him come along.
Slowly they get ever closer to Syhl shallow, but they still needed horses, so they go to a town undercover and try to trade deer hide for horses, but they get found out by the royal guards, and they have a fight, but the royal guards had to leave since the townspeople had also joined in, but some of them had gotten injured, so grey attempts to heal them with his magic and he succeeds which also gains him their trust.
They stay there for a night’s rest then start moving again with horses this time.
They reach Syhl shallow, and Lia Mara is taken, and so is Lisak but the queen Karis Luran treats them nicely since she knows that grey is the heir and is hoping to ally with him, and he cannot deny since they have nowhere else to go.
Nolla Verin is now told to win Grey’s heart, so she often stays with him too.
Liask had broken the treaty and is now locked in the dungeons, one day while grey was dining with powerful people and grey had left the room for a while only to come back and find a guard slashed and close to death by the hands of the Scraver, who did it in command of Karis Luran, and she wanted to show the people her power by also showing them that grey does have magic and she makes grey heal him back.
The guard was actually punished for listening to Lia Mara in the night that she went to the royal castle, and in exchange for healing him, Grey asked back the Scraver.
Lia Mara was then always locked in her room, and she was not allowed to come out.
Hence, Grey started to send her messages through Lisak, who used to fly through her window, and that’s how she gets to know that they are planning to go back in ember fall and take back Grey’s throne though Grey isn’t entirely comfortable with fighting Rhen.
After days of Lia, Mara getting information through grey, grey climbs her window one day and asks her multiple times if she wanted to escape since he could take her, but she denies saying that the peace among their people is the most important thing so eventually he has to leave.
The next day, they were to get ready to go to battle, but before that, Grey had to prove his loyalty to Karis Luran in front of dozens of soldiers and generals, so she asks him to kill a traitor, and that is her own daughter.
Lia Mara is brought down by her sister who is heartbroken but grey doesn’t kill her and instead tries to save her. Still, the others get caught with arrows aimed at their heads, Karis Lurans tells her men to kill them but Grey uses his magic that he has been practicing.
He makes all the arrows miss while Lia Mara kills her mother with daggers then Nolla Verin tells the others that Lia Mara is the queen and bows down along with everyone.
In the end, the people of Syhl shallow along with grey go to ember fall to talk to Rhen but still, it does them no good.