Ten Million Fireflies by Marianne Rice

She wants to make up for her lonely past by doing something good for children. He wants to forget his past and stay the loner that he is.

She’s Brooklyn Ross, former Army sergeant and the reluctant recipient of a surprise five million dollars from her father—a man who gave her everything except love and support. So when she spends the cash on a deserted summer camp for kids who need just that, Brooklyn figures her future is looking bright. It doesn’t hurt that there’s a sexy neighbor with soulful green eyes right next door, who makes her laugh and challenges her at the same time. Because challenges are her specialty.

He’s Drew Beckett, an author who is definitely not facing writer’s block. And he’s absolutely not distracted by the gorgeous, nosey woman who thinks she’s going to make a project of the camp next door. He has a history with that property, and he has no interest in dredging up the guilty secret that comes with it. No prying neighbor is going to bring down the walls he’s built around his home… or his heart.

Until he meets Brooklyn.