Mate

Mate is a romantic fantasy novel by New York Times bestselling romance author Ali Hazelwood. Originally published by Berkeley Romance in 2025, Mate is the sequel to Hazelwood’s 2024 novel, Bride. When the protagonist and first-person narrator, Serena, discovers she is a hybrid, or part-Human and part-Were (werewolf), she is forced into hiding, afraid that Vampyres, Humans, and Weres will reject her. She ends up in the company of the Northwest Were pack under the guard of Northwest Alpha, Koen Alexander. What begins as a frosty acquaintanceship gradually develops into a complex forbidden romance as the novel explores themes including Consent and Agency in Romantic Relationships, Romance as Rebellion, and the Finding Identity and Belonging Through Connection.

This guide refers to the 2025 Berkeley Romance paperback edition of the novel.

Content Warning: The source material and guide feature depictions of sexual content, cursing, illness, graphic violence, death by suicide, and death.

Plot Summary

This novel takes place in the world established by Hazelwood in the first book in the series, Bride. In the series world, Humans, Vampyres, and Weres (werewolves) all exist and have established their own societies and power structures, striking an uneasy balance that is challenged by a cult known as the Favored.

Twenty-five-year-old Serena flees her safehouse in the Southwest woods to escape a Vampyre pursuing her. Serena recently discovered that she is part-Human and part-Were, or a hybrid person. She went public with her unprecedented identity in hopes of deflecting attention from the only other known hybrid, Ana. A mysterious bounty was placed on her head, and she hasn’t been safe ever since.

Serena’s Were mate, Koen Alexander, shows up amidst her scuffle with the Vampyre and shepherds her to safety. A few months ago, Koen informed Serena that they were meant to be together. Serena is tepid towards sex and romance and still can’t adjust to this new reality: When you find your mate, you experience physiological changes that compel you into a sexual relationship with your partner.

Serena is doubtful that she and Koen could ever be together, but his behaviors confuse her. He informs her that he isn’t interested in her while simultaneously spearheading her care and safety. He takes her to his cabin in the Northwest woods and insists she stay here. He is worried that the Vampyres are threatened by her very existence, that the Humans want her as their political pawn, and that a secretive Were cult, the Favored, might regard her as evidence of their late leader Constantine’s power. (Constantine promised his Human followers he would turn them into Weres, all while failing to follow through and destroying Were packs.)

Throughout Serena’s time at Koen’s cabin, her feelings towards him become increasingly complicated. She is sensually overwhelmed by his scent. The house is perfumed with his intoxicating odor, and she somehow ends up sleepwalking to his bed every night. However, Koen continues to push her away.

Meanwhile, Serena harbors her own secret: She recently discovered that she has a chronic cortisol condition. While common and treatable in typical Weres, the illness manifests differently in Serena’s hybrid body. The doctor gives her a three-to-six-month prognosis. Serena gets frequent fevers, can’t sleep, is anxious and ornery, and lashes out in bouts of uncontrollable violence. She also loses her ability to shift into a Were. She hides the truth from Koen and her absent best friend, Misery; she does not want them to suffer on her account.

One night, Koen finds Serena trying to abate one of her fevers in the bathroom. He rushes to her aid, runs her a bath, and holds her until she falls asleep. In the morning, he confronts her about what is going on. He takes her to a doctor and demands a remedy. The doctor’s wife, Layla, is a midwife, and she looks into Serena’s case. Layla soon discovers that Serena is going into Heat, also known as Estrus.

Serena is desperate to prevent Estrus but feels conflicted because of her deepening feelings for Koen. Then one day, she discovers through a fellow Were that Koen will never sleep with anyone or pursue a relationship. Northwest Alphas (or leaders) are bound to uphold a celibacy covenant, which forbids them to be sexually, platonically, or romantically intimate with anyone.

Serena’s fevers worsen as Estrus nears. She meets with Layla again and begs her to prevent her from going into Heat. Layla explains that she can take other sexual partners during Estrus to survive the intense phase, but Serena only wants to be with Koen. Koen now knows the truth, and he doesn’t want to see Serena with another partner, either. Finally, Layla tells Serena that she and Koen should just have sex. She will keep Serena’s secret as long as Serena returns Koen to the pack after her Heat ends.

The pack is protective of Koen because he reunited them years before. When Constantine’s cult, the Favored, attacked the Northwest, he killed Koen’s parents and created divisions between the pack’s smaller groups, or huddles. Koen has kept them together ever since and protected them against the Humans, Vampyres, and Favored. The Favored are now reemerging, and Koen’s pack fears another attack by Constantine’s successor, Irene.

Serena is kidnapped by Irene, who begs her to return to the Favored, informing her that Constantine was her father, and her mother was his Human wife, Fiona. Irene argues that she belongs to the Favored and is evidence of Constantine’s power. Serena refuses. Koen arrives, and the two escape. Afterward, they hatch a plan to defeat Irene.

Serena and Koen spend Serena’s Heat locked in Koen’s cabin. They spend days engaged in passionate sex. Their physical intimacy deepens their bond, but they must part ways immediately afterward. Serena returns Koen to the Northwest as promised and offers herself to them as bait for the fight against the Favored. She will let Irene capture her to initiate an ambush. The plan works, and Serena and Koen successfully bring down the Favored.

Serena makes plans to return to the Southwest, but Koen informs her that their relationship isn’t over. He has talked to the Assembly (the pack council), and they have decided to eradicate the celibacy covenant. He can stay in a relationship with Serena and remain Alpha.

In the Epilogue, Serena and Koen are living a blissful life together. The only problem is that they still haven’t given each other love bites. When Serena finally bites Koen’s neck during sex one night, he is euphoric. He bites her back, and the two are bonded for life.