A bio-warfare scandal from the 1940s takes Sarah to a remote island in the Indian Ocean. She pursues the scoop with a fellow journalist from her former company, Planet 3. But why won't she contact her friends back in the UK? Josh and Natalie discover that Sarah has been searching for pursuers in the rear-view mirror for so long that she hasn't noticed who's now in the driving seat. A long way from home, and far from safe, will Sarah see the dangers in her present and the enemies from her past — before it's too late?