Reach for the Spy — Diane Henders

Middle-aged bookkeeper Aydan Kelly never wanted to moonlight as a spy, but she doesn't have a choice. Working with computer networks in a secured building sounds safe, but it turns out the job's a killer - literally. When Aydan's trusted co-worker is shot while committing an apparently treasonous act, Aydan embarks on a secret mission to clear his name. But her investigation casts suspicion on the director of operations himself. If he's a double agent, Aydan's in more danger than she ever imagined... and national security hangs in the balance. - Spicy suspense served hard-boiled -