Season 8 of "Castle" will see Ryan (Seamus Dever) and Esposito (Jon Huertas) welcome another child together, only the experience won't just be about good times.

New executive co-showrunners Alexi Hawley and Terence Paul Winter recently confirmed to TV Guide that the journey marks a big change in the lives of both characters and ultimately leads to Ryan "being even more paranoid and more excited about trying to make more money."

Seeing Det. Kate Beckett (Stana Katic) rise to the rank of captain only adds to all the angst that Ryan and Esposito are suddenly feeling about their own futures, ultimately creating "tension and conflict between them."

It's unclear what the show's new bundle of joy could ultimately mean for any potential Castle (Nathan Fillion) and Beckett baby-on-the-way plot-lines.

Whatever is decided on that front, both Hawley and Winter are taking added measures to stress that Hayley, the new security specialist character, played by Toks Olagundoye, will not pose a threat to the two co-stars' union.

"That was never our intention," said Hawley. "It's not going to happen."

In fact, with all the changes slated for the two this season - Beckett's new job and Castle's new work partner - if anything, early indications are they may be close to reaching a point where they come to rely on and need each other even more.

"It's always been about the Castle-Beckett love story," said Winter. "That's steeped in the DNA of the show, and that's what it will always be."

That's not to say, as always, there won't be twists and turns on the horizon.

"Now, it's about exploring the next evolution of it," added Winter. "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?"

The season premiere is slated for Monday, Sept. 21 at 10 p.m. EDT on ABC.