In the Veins of the Drowning

In the Veins of the Drowning (2025) is a romantasy (romantic fantasy) novel by debut author Kalie Cassidy. The story follows a Siren named Imogen who makes a deal with a foreign king, Theodore: his help escaping from her cruel, sheltered life on the isle of Seraf in exchange for her help in hunting down the Siren-killing water deity, Eusia. After forging a Siren blood bond to keep their promises, Imogen and Theo are forced to challenge their prejudices, learn the healthy balance between honoring one’s duty and indulging one’s desires, and confront the dangerous and unsightly consequences of pursuing too much power.

In the Veins of the Drowning is the first installment in a romantasy duology, followed by In the Wake of the Ruined (2026).

This guide is based on the e-book edition published by Hachette Book Group in 2025.

Content Warning: The source material and this guide feature depictions of sexual content, death, emotional abuse, and cursing.

Plot Summary

In the years since Imogen Nel discovered she was a Siren, she’s been living a dangerous life in hiding with fellow Siren Agatha—her friend, former governess, and only confidant. The rest of their world accepts the existence of Sirens, and some kingdoms even honor the Great Goddess Ligea who represents them. However, Imogen and Agatha live at Fort Linum on the isle of Seraf, which is ruled by King Nemea—the only king who openly hunts Sirens and worships the water deity Eusia instead of Ligea.

As the orphaned ward of King Nemea since infancy, Imogen is subject to his whims—the most recent of which is her engagement to the captain of his Siren-hunting forces, Evander Ianto. At her engagement feast, Imogen meets Theodore (Theo) Ariti, the duty-bound and devout king of Varya and grandson of the God Panos, who is known for his magical ability to grow and mend. Theodore is unabashed in his dislike for Nemea. He disagrees with Nemea’s dedication to hunting Sirens and is disgusted with his spiteful worship of the water deity Eusia instead of the Great Goddess Ligea.

On the night of Imogen’s engagement feast, she becomes intimate with Evander. The salt spray on his skin triggers her Siren transformation, causing Imogen’s wings and talons to emerge. Though he initially attacks her, he allows her to live and returns the next morning with a plan: Evander will keep her secret and marry Imogen, but in return, she will forge a Siren blood bond with him. This will give Evander immunity to Siren lures and grant him the power and influence he craves among his soldiers and in the kingdom.

Everyone is summoned to King Nemea’s ritual room, where the court is forced to offer their blood and chant a blessing for Eusia. Theo abruptly kicks over the bowl of Imogen’s blood, ruining the ceremony. Desperate to escape her impending marriage and secret blood bond to Evander, Imogen begs Theo to help her escape. His duty to his kingdom prevents him from risking a war with Nemea, but he promises to discreetly send aid for her in a few months.

That night, Evander visits Imogen’s chambers. He fills a tub with sea water and uses a siphon to force it into her lungs, triggering her transformation so they may complete the blood bond. Before he can cut their palms and exchange blood, Imogen hears a sultry female voice in her head that urges her to lure Evander into the tub with her, where he drowns.

Unable to wait a few months for Theo’s rescue, Imogen visits his chambers, where she intends to surprise him with a blood bond that will force his hand. She is unable to follow through and explains the situation to Theo. He agrees to a blood bond willingly, on a few conditions: Immediately after arriving in Varya, she will travel to the Mage Seer to have their bond broken and receive a prophecy that Theo hopes will aid them in hunting down Eusia.

Imogen and Theo bind themselves to each other and, with his retinue of guards, his commander Lachlan Mela, and Agatha, they escape the isle of Seraf. On the journey to Varya, they encounter nekgya in the water, which Imogen learns are undead sea creatures that hunt Sirens.

The bond causes Imogen and Theo sickness if they stray too far from each other, but it customarily settles in two days. However, upon arriving in Varya, it’s still affecting them. As a result, Imogen is forced to attend Theo’s marriage negotiations with the Empress of Obelia and her daughter, Princess Halla, instead of venturing on her own to meet with the Mage Seer. Meanwhile, Agatha and Lachlan yearn to rekindle a former romance they had a decade prior. They are still traumatized from the blood bond that Theo’s father forced them to break, as Agatha’s time at the Mage Seer’s hut during the severance nearly killed her.

With his wedding set to take place in a fortnight, Theo and Imogen rush to complete their journey to the Mage Seer and have their bond broken. Their journey takes days, during which they learn more about each other and begin to develop real feelings.

One night, they hear a distant scream and head to the near shore, where they discover a nekgya attacking a Siren and her young daughter. Imogen rushes into the sea to rescue the girl but is confronted by the leader of the nekgya, Eusia. Eusia claims that the blood offerings King Nemea forced Imogen to make to her all these years have created a blood bond with her. Imogen’s power has been fueling Eusia and the growth of her nekgya kingdom since. Amid this encounter, King Nemea’s ships reach Varya’s shores and attack Ammose and Notos.

After, Imogen and Theo reach the Mage Seer’s hut. Theo is knocked unconscious, and Imogen pays in flesh and blood for a severance draught vial. However, she learns that her bond with Eusia cannot be broken by the draught, for it was forged by a magic spell that can only be broken by its wielder—Imogen herself. Imogen receives a prophecy from the Mage Seer that confirms her parents are Ligea and King Nemea, and that what they made (Imogen) will destroy the order of all things. Later, Imogen informs Theo of the prophecy but omits the part about her bringing widespread destruction.

Upon returning to the castle, while Theo is preoccupied with engagement festivities, the Empress of Obelia pries into Imogen’s surname, Nel. She tells a story, implying that the Nel family was the first sacrifice King Nemea made to Eusia in exchange for power.

Theo and Imogen grow closer and become sexually intimate; their complicated feelings make them less inclined to take the severance draught. Meanwhile, Theo acquires old books on magic from the hermitess who controls the royal library. Through the books, Imogen discovers that Eusia is the First Mage Seer. Initially a Siren and the less powerful sister of Ligea, Eusia became greedy for power and mixed Siren blood with sacrifice to create a powerful magic that exacted a terrible price. To keep herself alive and feed her terrible magic, Eusia began demanding sacrifices of her worshippers in exchange for a miracle. The First Mage was thought to have been executed and thrown into the sea off the coast of Anthemoessa, the Siren’s homeland, which has long since been uninhabited due to blight and impassible waters. However, Eusia clearly survived.

With the stakes heightened, Imogen tells Theo of the prophecy’s ending, but he refuses to sever the bond. They attend an Obelian ceremony prior to Theo’s marriage, where Princess Halla initiates a blood sacrifice to Eusia that Imogen sabotages. She learns that the Empress has been serving Eusia long before King Nemea has—and is the one who taught him how.

Imogen takes the draught without Theo’s consent, severing their bond. Three days later, she is well enough to sail in search of Eusia, but King Nemea’s warships arrive to intercept her. Imogen uses her Siren lure to fight Nemea’s sailors but loses control over the lures because of her bond to Eusia. Sailors begin chanting their prayers to Eusia and throwing themselves overboard to their deaths.

Imogen confronts Nemea on one of his ships, where she learns his entire sordid backstory: Desperate for power, Nemea set out decades ago in search of the Mage Seers. When he learned the cost of their magic, he sought out Empress Nivala, who taught him how to worship Eusia in exchange for power. He asked Eusia to kill the Sirens terrorizing his fleets. In exchange, Eusia asked him to bring her home to Anthemoessa, where she sought to perform a spell to end Ligea. Nemea sacrificed the Nel family to feed Eusia during their journey, and afterward, on his return to Seraf, Ligea appeared. To protect herself from the deal he forged with Eusia, she bound herself to him. This caused him to protect her from Eusia for years, but when Ligea fell pregnant and sought out the sea to give birth to Imogen, Eusia took the baby and has fed on her power ever since.

Nemea casts a spell on Imogen he believes will protect her—and she learns that the Empress has taken Agatha as a Siren sacrifice for Eusia—just before she beheads him. Eusia appears afterward and claims Nemea cast the spell wrong. Eusia recasts the spell on Imogen, with different ingredients, which will allow Eusia to feed off Imogen’s power more efficiently. In exchange, she agrees to allow Imogen passage to Anthemoessa. After Eusia leaves, Imogen begins strategizing her three goals: kill Eusia, find Agatha, and keep Theo safe.