This is the second book in the Grishaverse trilogy.
Siege and Storm starts with our protagonists Alina and Mal who have left racks behind and they are in the city of cofton. The pair want to leave everything behind and have a fresh start but unfortunately for them, the antagonist The Darkling finds them and imprisons Alina once more along with Mal with the aid of his new powers to summon shadow monsters.
The darklings want to head north so as to find the second amplifier, the sea whip in order to fully control Alina’s powers.
The oncoming days become dazey for her as she is constantly under drugs. When she finally gets her bearings she realizes that they’re on a ship, she soon learns the destination the ship is headed and what they’re going for.
Just like the stag whose horns are currently resting on Alina’s neck, the sea whip is one of the legendary Morozova’s creatures and just like the stag, it is also imbued with magic.
Also, like the saath, the Darkling wants to kill the sea whip and turn it into an amplifier for Alina to wear even though no Grisha should ever wear more than one.
This is also the reason why the Darkling wants Mal as well because Mal’s hunting and tracking ability is second to no other.
Even though Mal and Alina don’t want to hurt the sea whip, the Darkling is forcing them to cooperate for the sake of each other.
The owner of the ship they are on is an infamous pirate Sturmhond a scourge of the seas that surround Ravka. Despite Alina and Mal’s pleas for help Sturmhond refuses to do so as he is being paid a lot in return for him to ignore their captivity, though Sturmhond does eventually give in and he helps the two escape. But by then Alina already has a better made of the sea whips scales around her neck, and her powers have grown stronger than she could have ever imagined. However, she still wants more.
Alina discovers a picture in a book that showed Sankt ilya painted along with a white stag, the sea whip, and a firebird. From this Alina theorized that the firebird would give her the perfect third amplifier and finally give her the power to defeat the Darkling once and for all.
Sturmhond then tells Alina that someone had paid him to get her to Ravka but he promises to help her leave if she doesn’t like what they have to say.
As they approached the shore they take a small boat that Sturmhond turns into a plane and they use that to fly through The Fold and Alina gets a vision of the Darkling talking to her. She panics and the plane crashes.
The king’s army approaches them and Sturmhond reveals himself to be Nikolai Lantsov who is the second son of the king.
He tells Alina that he wants to dave Ravka alongside her. Alina then tells him that she would help but not by marrying him, and she asks for the control of the Grisha army which was previously run by the Darkling. Nikolai agrees and they return to Os Alta where thousands of pilgrims had gathered to catch a glimpse of the sun-summoner saint Alina, whom they all believed would be the one to save them. The Apparat, a religious leader was said to be gathering a cult of the sun saint, many soldiers had even abandoned their posts to join the said cult.
Alina takes control of the remains of the Grisha army and starts to make plans for how to defeat the Darkling and his shadow monsters. However, the other Grisha were still resistant to her command and she continued to get visions of the Darkling.
On top of that, Mal was unhappy about returning to the palace and about Nikolai’s affection for Alina.
Alina goes to see Baghra, the Darklings mother to ask for help to find the firebird but Baghra refuses. Nikolai also starts to build another plane in case they need to escape quickly.
As the preparation for the battle was being made, Mal invites Alina to a party and they go and have fun, but then the Apparat corners Alina and asks her to come with him to join his army. She refuses and he disappears. She returns to the palace where she gets another vision of the Darkling and she also gets into a big fight with Mal. Alina also realizes that the firebird may be her hometown of Dva Stolba, and Mal agrees to go search for it.
Before he left, they attend Nikolai’s birthday party where his brother Vasily reveals that he had made a deal with the Fjerdans that had involved their loyalty in exchange for the reopening of a few logging roads. Nikolai immediately senses that they had been double-crossed and the warning bells begin to ring as the Darkling arrives with his shadow monsters. Vasily gets killed while Nikolai escaped with his parents and Alina and Mal get cornered in the chapel with a few other Grisha.
Alina agrees to join the Darkling in exchange for the life of her friends whom he promises to let go. Alina feels her powers get merged with the darklings’ and she realizes that not only can he now control her powers, but she can also control his. She starts to create more shadow monsters until nearly the both died hoping to kill the both of them. But Mal stopped her and the two then escaped to the White Cathedral where the Apparat was hiding. Alina recovers from her injuries but finds that she can no longer use her powers and her hair turns white.
The Darkling takes over the throne and now Alina could only hope that her powers would return so that she can fight him.