The MacLeod Pirate by Caroline Lee

The Black Banner is the Western Isles’ most notorious pirate…and he’s about to meet his match!
Citrine is the last Sinclair Jewel left with any chance to save her clan, and she’s not about to fail them. But when she’s a victim of mistaken identity and taken prisoner by a gorgeous—and completely maddening—pirate captain, Citrine is afraid she’s missed her opportunity. But when she discovers the Black Banner holds one of her family’s long-lost jewels—and refuses to tell her why—she realizes their futures are connected.
Rory MacLeod is the youngest son of a powerful laird and is happy to let others rule as he spends his life at sea…as the Scourge of the Minch, the fierce pirate known as the Black Banner. When his father signs a betrothal contract with the Sinclair laird, Rory has no intention of following through with it. Little does he realize the beautiful firebrand he’s just kidnapped is the woman he’s supposed to marry!
Together, Citrine and the Black Banner might be able to solve one mystery…but the real threat to the future of the Sinclair’s is back at home.