“Bulletproof Christmas” is the 6th book in the “Crisis: Cattle Barge” series. The main character of the story is the tracker Rory Scott. In the story Tracker Rory Scott had an ex named Cadence Butler who was killed by someone and Rory Scott is targeting his ex to try to find the killer. He is shocked to find Cadence pregnant with his twins. The book tries to keep Rory and Cadence safe on the journey.