Downton Abbey season 4 airs its finale this evening, and we have a preview of the special extended episode.

UPDATE: Read our recap of tonight’s season 4 finale!

The Downton Abbey season 4 finale is technically the show’s “Christmas Special” for 2013. It aired on Christmas Day in the United Kingdom and was separated by several weeks from the previous episode.

For Americans, tonight’s episode is a 90-minute season finale that will close up some plot holes but open up others, and new romances may very well be introduced.

The synopsis for the episode is lengthier than usual because of the extended air time. “It’s the summer season and as part of Rose’s ‘coming out’ she is to be presented at Buckingham Palace. The family and servants are at Grantham House, their London residence, preparing for the busy social program. Not one to miss such a grand occasion, Cora’s mother, Martha Levinson makes the journey from New York with her playboy son Harold, fresh from his recent brush with the law. Both outspoken and larger-than-life, they make quite an impression amongst certain members of London’s high society, in particular with Lord Aysgarth, played by James Fox.”

It continues, “Isobel finds herself with an admirer while Edith is wrestling with a moral dilemma. Downstairs, Daisy gets an unexpected invitation and Carson treats the staff to a special day out. When the Crawleys are implicated in a scandal that threatens to engulf the monarchy, Robert will go to great lengths to protect the royal family, and his own.”

A clip from the episode depicts Ms. Levinson and Harold (played by Giamatti, who makes his first appearance in this scene) arriving at the Grantham House where the Downton residents are staying for Rose’s presentation to the King and Queen:

The Downton Abbey season 4 finale airs Sunday, February 23 at 9 p.m. eastern/pacific on PBS. Remember that the episode is 90-minutes in length, so don’t expect it to end until 10:30.

Watch ‘Downton Abbey’ online

You can watch new episodes of Downton Abbey online for free via PBS’s official website. Today’s finale should be released on their website tomorrow, February 24.