Det. Beckett may have slapped the cuffs on Sen. William Bracken at the end of "Castle" season six, but the man responsible for her mother's death will make a "surprising" return in the season eight premiere.

Jack Coleman will reprise his role as the dirty politician when the ABC series returns on Sept. 21 and will "be back in a surprising way," co-showrunner Terence Paul Winter told TVLine.

"Castle" will kick off the season with a two-part episode that will introduce new series regular Toks Olagundoye as Hayley Vargas, a former Scotland Yard officer turned security specialist, and the recurring tech analyst Vikram Singh, played by Sunkrish Bala.

Castle (Nathan Fillion) and Beckett (Stana Katic) will also encounter the mysterious Rita (Ann Cusack), a member of a top-secret organization who enters Beckett's life with a unique set of skills... and an unexpected connection to Castle, according to TVLine.

On the home front, Alexis (Molly Quinn) has a new hairdo that is part of a more adult makeover. The makeover also comes with a more adult (that's right, S-E-X) relationship for Castle's only daughter.

Katic teased earlier that the season premiere will revolve around "an event that shifts the entire season into a higher velocity" and "is part of what will set everything up for the next 20 episodes." The show will further explore Castle's disappearance and memory loss from last season as well as what made Beckett become a cop beyond solving her mother's murder.

"Castle" will return on Monday, Sept. 21 at 10 p.m. on ABC.