When They Come for You — James W. Hall

After her journalist husband and infant son are brutally executed in a fire in their Florida home, photographer Harper McDaniel has nothing left to live for -- except settling the score. When the local police fail to take the arson seriously, Harper takes the reins and discovers her husband was investigating some mysterious deaths at a cacao plantation on the Ivory Coast. Now she's convinced he was targeted in a corporate conspiracy to silence him.

Aided by her former mafioso grandfather and well-connected financier brother, Harper embarks on a global manhunt, flying first to Africa, then Zurich to expose a high-level cover-up inside a powerful chocolate conglomerate.

But Harper has a few secrets of her own -- starting with her lethal martial arts skills -- and she's not afraid to take on any hired guns or guerrillas standing in her way. In trying to cover their tracks, the conspirators made one fatal miscalculation: they didn't count on Harper McDaniel coming for them.