Only Human: Themis Files Book 3

Brilliant scientist Rose Franklin has devoted her adult life to solving the mystery she accidentally stumbled upon as a child: a huge metal hand buried beneath the ground outside Deadwood, South Dakota. The discovery set in motion a cataclysmic chain of events with geopolitical ramifications. Rose and the Earth Defence Corps raced to master the enigmatic technology, as giant robots suddenly descended on Earth's most populous cities, killing one hundred million people in the process. Though Rose and her team were able to fend off the attack, their victory was short-lived. The mysterious invaders retreated, disappearing from the shattered planet . . . but they took the scientist and her crew with them.