Four Corner Spread

Tribal police discover a body spread on the Four Corners monument.
When the head rolls away from the investigator's touch, they call the FBI.
San Francisco Medical Examiner's laboratory gets the body, and Muna calls Washington D.C. Even though Nash is already involved in a case, they assign the unusual body case to her and Powder.
The more she investigates the unusual nature of the body, the more personal it becomes.
Until a bomb explodes...