Mark of the Lion is started on the battlefields of France in WWI. It then moves to Africa after the war. There were some bits that didn't sit comfortably with me - historically. It felt much more like a post WWII book than WWI. The main character, Jade, drives battlefield ambulances in France during the war. Her boyfriend, a pilot dies, and she is lead to understand (by his last words) that he has a brother that he wants her to find. The hunt for the brother leads her to Africa, where she runs afoul of a local witch doctor.
One of the things I did appreciate about this book is that the inevitable romance was written quite differently to normal fictional romance. Bit hard to explain without giving away key parts of the story but suffice to say there was internal conflict and the resolution was a little different to what I've come to expect.
On the whole; however, the central character, Jade, seems almost too good to be true. She shoots, rides, drives. The only thing that gets to her is the hyena's laugh (a reminder of her battlefield experiences with mentally unstable wounded GIs). Other than the laugh, she's pretty much bullet proof.
I'm not sure I would go out of my way to read anything else by this author, so I give it a 4.