When a series of corpses with ties to Booth's former Army unit appear around D.C., Booth must dive into his past to find the killer before the killer finds Booth. Meanwhile, Brennan's father, Max, hides a serious medical procedure from Brennan, leaving her to grapple with her father's trust and mortality, as well as her family being in danger.

When a young man dies in a horrendous hay baler accident, Booth, Brennan and Aubrey slap on trashy disguises and go undercover at a rowdy demolition derby competition to investigate the case. Meanwhile, Dr. Gordon Wyatt returns and assists Hodgins and Cam when the ongoing Gormogon case hits a dead end.