The body of a documentary filmmaker leads the team to investigate a series of tunnels underneath D.C. inhabited by homeless people and possibly containing a vault of Civil War-era treasures long thought missing.
Tropes
- Insane Equals Violent: Subverted. Herold, the Shell-Shocked Veteran living underground, is clearly dealing with some mental health issues but not only is he in no way responsible for the murder he is in fact a calming influence on the underground community he lives in.
- Shout-Out:
- Booth can't believe Brennan has watched The Treasure of the Sierra Madre.
- Booth makes one to tabletop game Cluedo when he describes the final showdown as "Kyle hit Duke with the candlestick in the crypt". Goodman lampshades it.
- Running Gag: Zack, Goodman, and Angela all refuse to "officially take possession of that piece of evidence".
- Shell-Shocked Veteran: A significant character is a veteran with severe PTSD who has chosen to live and hide in the tunnels under DC, acting as a de facto mayor for the community of outcasts there. Booth strongly identifies with the man because he, as a former sniper, has also killed a lot of people, up close and personal.
- Wainscot Society: Booth and Brennan investigate the death of a woman who was investigating the underground denizens of Washington DC, who are depicted as forming something of a distinct society; one of the main guest stars is a vet who suffers from PTSD and who lives down there.
