Ryan (Seamus Dever) and Esposito (Jon Huertas) will have some conflict in the upcoming season of ABC's Castle.

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The eighth season of Castle will feature some healthy competition between Ryan and Esposito.

The tension will arise when Beckett (Stana Katic) becomes the new precinct captain. New Castle co-showrunner Terence Paul Winter spoke about Ryan and Esposito in a new TVLine report:

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"After seeing Beckett ascend the ranks, they're realizing maybe it's time for them to start looking upwards in their own careers," he said. "In doing so, they start to butt heads a bit, but in a fun way, because the dynamic between those two has always been 'two brothers.'"

This conflict also arises from Ryan and his wife Jenny (Juliana Dever) having a baby.

"We have some exciting news for the Ryan family: They're expecting another kid," Winter told TVGuide.com in a new interview. "Ultimately, that's going to make Ryan even more paranoid and more excited about trying to make more money."

He also spoke about how Castle (Nathan Fillion) and Beckett's relationship will continue to be the crux of the crime procedural.

"It's always been about the Castle-Beckett love story. That's steeped in the DNA of the show, and that's what it will always be," Winter said. "Now, it's about exploring the next evolution of it. How do we deepen that love story? What challenges can we put their way that can put their romance at a much higher, different place?"

Castle season 8 premieres Monday, Sept. 21 at 10 p.m. ET/PT on ABC.