Castle and Beckett don spacesuits and enter a Mars simulation to figure out how an astronaut ended up dead on Castle. "The Wrong Stuff" is the 16th episode of the show's seventh season.
One of the best things about "Private Eye Caramba!" was the Caskett role play. Kate Beckett was "just a girl looking for a private dick." Looks like she found one.
The best part about the "Reckoning" was that for the first time in the series, a Castle two-parter ended with Rick and Kate getting through it together.