Gunner by Winter Sloane

Gunner didn’t do relationships. As the enforcer of the Iron Sentinels, his world was brutal, dangerous, and full of enemies. But when Dawn stumbled into his life, all fire and attitude, she flipped his world upside down. He told himself she was off-limits—too good for a man like him. Then she became his, and nothing would stand in his way to protect her.
Dawn never expected to fall for a biker, let alone one as ruthless and fiercely loyal as Gunner. But just as she starts to feel safe in his arms, her past comes back with a vengeance. Threatened by a stalker who wants to destroy her, Dawn fights to survive, knowing Gunner will come for her. And when he does, there will be no mercy.