Safe Before Dawn by Linda Castillo

Chase Vickers never knew a day of fear. From one secret mission to another he'd stared down danger until the blackout hit Boston, and Chase's only love became the target of revenge. Lily Garrett, the woman he'd loved and walked away from eight months ago. Finding her wasn't difficult; finding her pregnant was.

Lily had always hated Chase's secret, dangerous life, but now, on the run in a dark city, Chase knew he washer only hope for survival. And their baby's. For the first time, the daredevil–turned–daddy knew bone–chilling, pulse–pounding fear. This was one mission where he couldn't fail. Not when his baby's life was at stake