The Relentless Mate by Kira Nightingale, June 28th 2025
She’s the mark he should betray. He’s the temptation she can’t resist. A bond between them isn’t just dangerous – it could be fatal…
Annabella
I’ve built a life on secrets and strength. As the leader of a covert rebel crew hellbent on tearing down the corrupt Wolf Council, I’ve survived by trusting no one—not alphas, not mates, and definitely not smooth-talking operatives with charming smiles and hidden agendas.
But the new guy is different. Infuriatingly attractive. Recklessly brave. And a complication I don’t need. Every time he looks at me, it’s like he sees too much. Wants too much. And I want him right back. That’s a problem I can’t afford.
Sam
I’m deep undercover, embedded in enemy territory with one mission: gather intel and neutralize the threat. What I didn’t plan for was Annabella McGrath—the sharp-tongued, fire-hearted rebel who makes me question everything.
She’s supposed to be the target. But the more time I spend with her, the more I’m drawn in by her strength, her fire, her fight. I’m playing a dangerous game, and if she finds out who I really am, we could both burn.
Their chemistry is explosive. Their secrets are deadly. And when the truth comes out, all hell will break loose.
The Relentless Mate is the gripping first half of Sam and Annabella’s story—a steamy, high-stakes romance full of secret identities, enemies-to-lovers tension, found family bonds, and fated mates at war with their destinies.
This book ends on a cliffhanger. Their HEA is in The Resurgent Mate (Book 7).
Click Buy Now to dive back into the Shifters of the Three Rivers world—where rebels rise, hearts collide, and fated mates face their fiercest test yet.
Shifters of the Three Rivers (complete series)
Book 1: The Runaway Mate (Ryan and Mai)
Book 2: The Renegade Mate (Ryan and Mai)
Book 3: The Resolute Mate (Ryan and Mai)
Shifters of the Three Rivers omnibus: Books 1-3, Ryan and Mai’s story (ebook only, with an exclusive epilogue)
Book 4: The Rescued Mate (a Mason and Shya story)
Book 5: The Reluctant Mate (a Derek and Sofia story)
Book 6: The Relentless Mate (a Sam and Annabella story)
Book 7: The Resurgent Mate (a Sam and Annabella story and the explosive finale in the series)
Books 4, 5 can be read as standalones. Book 6 and 7 are a duology.
Novellas:
A Three Rivers Holiday Tale
Cover arts: 100 Covers