TVLine can now reveal another intriguing piece of the puzzle that is Castle‘s Season 8 premiere.

As previously reported, the ABC procedural will return Sept. 21 with a two-parter, the first installment of which is titled “XY.” The double-episode salvo will introduce two new characters: Scotland Yard officer turned security specialist Hayley Vargas (to be played by new series regular/Neighbors alum Toks Olagundoye) and tech analyst Vikram Singh (recurring player Sunkrish Bala).

What’s more, Ann Cusack (Private Practice) will guest-star in Part 2 of the premiere as Rita, a member of a top-secret organization who drops into Beckett’s life with a unique set of skills… and an unexpected connection to Castle.

Now you can add to the mix the return of the forever-nefarious William Bracken, to again played by Jack Coleman. The disgraced senator, who pulled many puppet strings in orchestrating Johanna Beckett’s years-ago murder, will “be back in a surprising way,” new co-showrunner Terence Paul Winter tells TVLine.

Interestingly, with Castle back Sept. 21 and NBC’s Heroes Reborn launching Sept. 24, Coleman fans are poised to get a double helping of the actor, who last played Bracken in Season 6’s penultimate episode, “Veritas,” when the ambitious politician saw his White House bid handcuffed by, well, handcuffs.

Want more scoop on Castle, or for any other show? Email insideline@tvline.com and your question may be answered via Matt’s Inside Line.

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