How will Ethan Slaughter (Adam Baldwin) figure into the current season of ABC's Castle?

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Slaughter is returning for another episode of Castle, reuniting with his former Firefly costar Nathan Fillion, who plays Castle on the series.

Castle showrunners Alexi Hawley and Terence Paul Winter spoke about Baldwin's return as Slaughter in a new interview with Entertainment Weekly.

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"Given everything that happened in season 4 between [Slaughter and Castle], obviously Castle's very hesitant," Hawley said. "But we want to do something unexpected with it, to turn the story a little bit on its head, so it's not going to be just a carbon copy of the episode we had before. We have some really great twists and turns."

"We're going to see a new side of Slaughter that we weren't privy to in the first episode that we saw him in," Winter added.

Longtime fans will recall Castle following Slaughter on a case in the season 4 episode titled Headhunters, though he eventually tired of Ethan's rough and tumble ways.

This marks another reunion of Fillion and Baldwin, whose show Firefly has become a cult classic. The sci-fi western series took place 500 years in the future and centered on a group of renegades traveling through space and getting into all sorts of adventures while trying to avoid capture. The series lasted one season on Fox from 2002-03.

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

Tags: Castle television ABC