: The title refers to the bioweapon case but also nods to the historical German plot to assassinate Hitler, a connection Esposito points out during the investigation.
: Moving the action to D.C. makes the episode feel more like a "generic action-thriller" compared to the charm of the 12th Precinct. [S6E1] Valkyrie
Critics from Den of Geek and fans on Reddit highlighted several key shifts: : The title refers to the bioweapon case
“We all know Castle won't die, but then again I suppose that's not really the point of the cliffhanger.” Reddit · r/CastleTV · 12 years ago Notable Moments & Trivia [S6E1] Valkyrie
: This marks the first time a Castle season premiere ended on a two-part cliffhanger.