Waiting for Magic — Susan Squires

Keelan is the middle sister of the large and successful Tremaine family who are descended from Merlin of Camelot. His magic in their DNA only comes alive when each meets a destined lover who shares the gene. Two of Keelan's siblings have found true love and magic powers they can use to help the family in their fight for survival against the Clan, whose magic comes from Morgan Le Fay. Just Kee's luck she's fallen in love with someone who doesn't have the Merlin gene. Now she'll never get magic. She's afraid to tell her even her best friend, Devin, that she's about to give up on her destiny. They've lived like twins since Devin was adopted by the Tremaines when he was nine. Now their paths are diverging, painfully. Devin has his own problems. He harbors a secret that's driving him to leave the family for good. He never felt he belonged anyway. To repay them for their kindness, he vows to acquire the Talisman that can protect the Tremaines from the Clan. And only Kee can keep him from making the ultimate sacrifice.