The Season 8 premiere of "Castle" will be a two-part feature used to introduce several new characters to the worlds of Richard Castle (Nathan Fillion) and Det. Kate Beckett (Stana Katic).

TV Line reports Part 1 of the Sept. 21 season-opener will be titled "XY" and introduce new characters Hayley Vargas and Sunkrish Bala. Played by "Neighbors" alum Toks Olagundoye, Hayley is billed as a former Scotland Yard officer turned security specialist and Vikram Singh will assume the role of tech analyst Bala.

Part 2 of the episode will also be used to introduce onetime "Private Practice" star Ann Cusack to the cast as Rita, further described as 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."

Also reprising his role as wayward Sen. William Bracken in the season opener will be Jack Coleman. Bracken, who among his last show sightings was still pulling the strings in the murder of Johanna Beckett, is touted as returning "in a surprising way."

The Vine Report previously reported with her working closely with Castle, "there is a strong possibility" that Olagundoye's character could cause discord for him and Beckett. Complicating the situation all the more is the fact that Hayley's emergence comes at a time when Beckett might be a bit distracted, as she entertains thoughts of making a run at political office.

According to TVLine, Fillion recently tried to calm the fears of many fans concerned about his and Beckett's relationship by sharing change is "crucial to the success of the show."

Already, Penny Johnson is known to be not returning the show as Captain Victoria Gates, and show runner David Amann is also out, being replaced by the tag-team of Alex Hawley and Terence Paul Winter.