The episode picks up with the immediate aftermath of the Season 5 finale: Kate Beckett’s move to Washington D.C. for an FBI task force and her acceptance of Rick Castle’s marriage proposal. The "honeymoon phase" is quickly cut short when Castle, unable to resist meddling in Beckett’s new federal world, finds himself accidentally contaminated with a deadly, airborne chemical bioweapon.
“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
: 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. The episode picks up with the immediate aftermath
: Despite the distance, the episode leans into "shipper heaven" with domestic morning scenes and Beckett wearing her engagement ring on a necklace. “We all know Castle won't die, but then
While the episode succeeds in raising the stakes, it faces some criticism for its dialogue and the "melodramatic" nature of its ending.
The Castle Season 6 premiere, is a high-stakes departure from the show’s usual procedural rhythm, effectively resetting the status quo while delivering one of its most literal cliffhangers. High Stakes and Heavy Toxins
: This marks the first time a Castle season premiere ended on a two-part cliffhanger.