The Strong Tower

MaKenna Dunne had moved to a small town on the shores of Lake Erie to take a position as a medical office assistant, trying to escape from a restricted lifestyle. Ciaran Quinn, a renovator in the small town is called in to help his sister, Beth's friend, after a windstorm brings down multiple limbs. Finding a small rusty box in her yard, Ciaran and Beth open it to find a small key.
MaKenna and Ciaran face kidnappings of MaKenna, assaults on them both, attempted murder of Ciaran, and the realization that the man MaKenna and her brother, Riordan thought all along was their father, was really a step-father, a brutal man who didn't stop at assaulting their mother over their years, finally assaulting her enough to hospitalize her and give Riordan a chance to remove her from the home she had shared with Darby Dunne.
Together, Ciaran and MaKenna faced their troubles and despite separations and near death, they grew closer to one another, helping each other to stand strong and face their enemies and find their faith in God strengthened.