Ep 16. The Wrong Stuff

In season 7, episode 16 of Castle, titled "The Wrong Stuff," the team investigates the murder of an astronaut who was training for a Mars mission on a simulated spacewalk. Castle and Beckett explore the astronaut's past and current relationships to determine if his death was connected to his personal life or his work at the space center.

The investigation leads the team to NASA, where they encounter a group of competitive and highly-skilled astronauts who are all vying for a spot on the upcoming Mars mission. The competitive nature of the astronauts makes it difficult for Castle and Beckett to determine who may have had a motive for murder.

As Castle and Beckett dig deeper, they discover that the missing sample of precious Martian moss that the astronaut was responsible for may have played a role in his death. As tensions at NASA rise, the team must race against time to find the killer before more lives are put at risk.

Meanwhile, Castle's creativity is put to the test once again as he tries to come up with a storyline for his new book. Beckett encourages him to think outside the box and approach his writing in a new way, which ultimately leads to a breakthrough for the author.

Throughout the episode, Castle and Beckett continue to work through the challenges they face in their relationship and attempt to strengthen their bond. They lean on each other for support as they navigate their personal and professional lives, and reaffirm their commitment to each other.

Overall, "The Wrong Stuff" is a thrilling and suspenseful episode that takes viewers on a journey into the high-stakes world of space travel. Castle and Beckett must use their skills and intuition to solve the case, all while juggling the ups and downs of their own relationship.