Now that Kate Beckett is back in the arms of Rick Castle, it seems all will be back to normal. After the suspense-filled episode of last week, seasoned viewers will now see the two lovebirds and mystery-solvers back to their crime-fighting days.

Episode 16 of season seven will have a mystery that is sure to entice audiences and captivate their attention. According to the episode's synopsis by TV Guide, Castle and Beckett will tackle the murder of an astronaut. The astronaut dies in a sealed simulation chamber where no one can go in.

The astronaut was training for a trip to Mars and it seems no one inside the sealed chamber could have committed the murder and no one from outside could enter, so how did they die? It seems a fitting Castle-Beckett case after the events of episode 15. Castle and Beckett will be clad in spacesuits as they are set to investigate the intriguing circumstances surrounding his or her death.

Additionally, showrunner David Amann confirmed the mysterious case in an interview with TV Guide. He said, "It's basically murder on Mars. There's a Mars simulation with astronauts who've been locked away in a Mars environment for six months, and one of them is murdered. But none of them could have done it -- nobody could have gotten in. So Castle and Beckett have to put on spacesuits and go talk to people." In an interview with TVLine, Amann also specified that this episode will be a sort of palate cleanser.

Moreover, Kate is now thinking about her career as Amann explains, "And as part of that, we think that moving forward there is this kind of an ongoing theme for Beckett about what it is that she wants to do next with her life and her career. That's going to be something that manifests in the episodes moving forward."

Which means, Kate will seriously start thinking about her next career move. Watch a classic Castle episode as "The Wrong Stuff" airs on Feb. 23 at 10 p.m. on ABC.