When Rachel Harrington's bones are found in Zambia, her expat father and local mining engineer, Stephen, asks the team to come out to investigate. His boss, Peter, is a childhood friend of Nikki's. Rachel had been accusing the government of a health cover-up, and an initial examination shows evidence of multiple stab wounds. But as the team investigates further, it seems the government weren't the only ones to have been rubbed up the wrong way by Rachel.