'Castle' Season 6: 'Justified' actor Joelle Carter to guest-star

"Castle" is getting a visitor from "Justified." Joelle Carter, who stars as Ava Crowder on the FX drama, will guest on "Castle" for the seventh episode of the upcoming Season 6, according to TVGuide.com.

Carter will play a character named Maggie Ingram. The long-time girlfriend of a death-row inmate, Maggie crosses paths with Castle ( Nathan Fillion) and Beckett ( Stana Katic) when her man is set for execution. Does she believe he is innocent? Or is there another crime in addition to the prisoners?

Alas, that is not yet known. The only other tidbit of the episode, "Like Father, Like Daughter," is that Alexis ( Molly Quinn) will be getting involved with the case, just like her dad.

A notable character since the beginning of "Justified," Carter's Ava has gone from a vengeful battered wife (with a shotgun) to the co-runner of a criminal empire (with a shotgun) in four seasons. Ava ended Season 4 in jail for crimes that she totally committed with her main man, Boyd Crowder ( Walton Goggins).

"Castle" Season 6 premieres Monday, Sept. 23 at 10 p.m. on ABC.

Photo/Video credit: FX