Adam Baldwin returns to the cast of "Castle" for Episode 6 of Season 8, entitled "Cool Boys."

According to TVLine, Baldwin will reprise his role of Det. Ethan Slaughter in the upcoming episode. Fans last saw Slaughter during a Season 4 episode, in which he worked side-by-side with Castle (Nathan Fillion) to solve yet another crazy mystery.

Granted, not much seems to bring joy to Castle these days, given his split from Beckett (Stana Katic). But it's worth noting he didn't exactly relish his work with Slaughter the last time they were partnered. In that episode, entitled "Headhunters," the unconventional detective seemed to rub the novelist the wrong way with his questionable tactics.

The somewhat wayward lawman has been described by some media outlets as "downright crazy," displaying a tendency toward violence with suspects. Viewers may recall his antics nearly got Castle killed in "Headhunters," prompting Rick to vow never to work with him again.

But with Beckett gone, nothing seems to matter as it once did to Castle. In his desperation to woo back his wife, Episode 5 found him turning to a smell specialist for guidance. Speculation is the two could actually reunite once more sometime around Episode 8, during a "Mr. and Mrs. Castle" themed airing.

In addition, co-showrunner Alexi Hawley recently told TVLine the show's new split-season scheduling format won't allow for an annual Christmas-themed episode this year.

"Unfortunately, because of the way ABC is platforming us -- we do eight episodes and end [Nov. 23], and we're not on again until the beginning of February," he said.

"Castle" also stars Jon Huertas as Javier Esposito, Seamus Dever as Kevin Ryan, Molly Quinn as Alexis Castle and Toks Olagundoye as Hawley Vargas.

Episode 6 of "Castle" Season 8 will air on Monday, Nov. 9 -- not on Nov. 2, due to a scheduling conflict -- at 10 p.m. ET on ABC.