Sonja Kurtz – former soldier, supposedly retired mercenary – is in Vietnam carrying out a personal revenge mission when her daughter sends a call for help. Emma is on a dig at the edge of Namibia's Etosha National Park studying archaeology and she's discovered a body that dates back to the country's liberation war of the 1980s. The remains, identified as Hudson Brand, are a key piece of a puzzle that will reveal the location of a modern-day buried treasure. A find people will kill for. Sonja returns to the country of her birth to find Emma, but she's missing. Former CIA agent Hudson Brand is very much alive and is also drawn back to Namibia to finally solve a decades-old mystery whose clues are entombed in an empty corner of the desert.