Nightwatch (The Defenders, 1)

Fire captain Mitch Andrews can't forget the three young children he saved from a fire. A suspicious fire that left them orphans. In the care of foster mother Jill Kirkpatrick, he knows the little ones will be loved. Even if the sweet, strong widow won't let Mitch close to her. But suddenly the kids—and Jill—are in terrible danger…and one of the children is missing. Mitch and Jill will risk everything to find the stolen girl and keep a makeshift family of five together forever.