Castle creator Andrew W. Marlowe recently teased what was in store for the season 7 finale, which explores why Castle (Nathan Fillion) became a writer.

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Marlowe spoke with TVGuide.com in a new interview this week, discussing the final episode of season 7 and what it will mean for both Castle and Beckett (Stana Katic).

"We get some answers as to why Castle became a mystery writer," Marlowe said. "It centers on an event that happened to him when he was 11 years old. We get to go way back into Castle's backstory in a case that has eerie similarities to something he dealt with when he was a kid. So, it opens up some old wounds and leads to a bit of an obsession as he starts exploring some of the issues surrounding the case."

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Meanwhile, Beckett will be left with a decision to make as she tries to weigh the options of becoming the new captain and potentially raising a family with Castle.

Beckett has "some very interesting choices as far as her career is concerned," Marlowe said. "It's more complicated than just issues within the NYPD."

As Castle fans know, the show has been in slight turmoil through much of the season due to Fillion and Katic renegotiating their contracts beyond season 7. Luckily Fillion just renewed his but Katic has yet to reach an agreement. It remains to be seen if Katic will sign on the dotted line in the next few weeks or if she will choose to leave the show.

Castle airs Mondays at 10 p.m. ET/PT on ABC.

Watch the promo for the next episode of Castle here:

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