Deep Dark by Amy Reece

Isabelle DeLuca is capable of juggling her family obligations and her career as co-owner of DeLuca Construction. What she can’t do is reveal the huge secret hidden in her past—not even to her best friend or her own mother. But when that mystery man suddenly appears again in the flesh, she’s forced to face the truth she’s tried so hard to hide. Then, while looking into a lead on a business associate, she stumbles across something big—big enough to get Homeland Security involved—and soon finds herself embroiled in an investigation of possible domestic terrorism. Who knew love—and bookkeeping—could be so hazardous?