NEW YORK — The third season of ‘‘Downton Abbey’’ ends Sunday night with a bang.
Exactly what that bang is, we’re not going to say, in deference to the maybe half-dozen ‘‘Downton’’ fans who still don’t know the shocking truth.
The larger point remains that after Sunday’s ‘‘Masterpiece Classic’’ (airing at 9 p.m. on PBS), viewers must suffer ‘‘Downton’’ withdrawal until next season.
And what a season this has been. The beloved valet Mr. Bates was sprung from jail and a trumped-up murder charge to begin married life with his bride, the plucky lady’s maid Anna. Robert Crawley, Earl of Grantham, has gotten Downton Abbey back on its feet financially with an able assist from his son-in-law and presumptive heir, Matthew Crawley. Matthew wed his true love, Lady Mary Crawley. But another of Robert’s daughters, Lady Sybil, died tragically during childbirth.
Through it all, Robert’s mother Violet, Dowager Countess of Grantham (played by the sublimely scene-stealing, Emmy- and Golden-Globe-winning Maggie Smith) delivered a barrage of withering, hilarious rejoinders to virtually every narrative twist.
‘‘I remember my very first scene with her in season one,’’ said Hugh Bonneville, who plays Robert, lord of the manor. ‘‘She’s complaining about the new electric lights, and suddenly she put her fan up to her face to shield herself from ‘the glare,’ and spent the entire scene like that. It was so funny, and I was just, ‘All right! There’s no point in my even being here. She’s just marched off with the scene!’ ’’
As the wealthy, patriarchal Lord Grantham, Bonneville exudes classiness and, at crucial moments, generosity.
But Robert Crawley is also confounded by the modern world of post-World War I as it upsets the social hierarchy. Meanwhile, despite his indulgence of underbutler Thomas Barrow’s shame (it seems Thomas is gay), Robert isn’t always the most tolerant of men.
‘‘I don’t want thumbscrews or the rack, but there always seems to be something of Johnny Foreigner about the Catholics,’’ he sniffs to one of his kind during an exchange about religion.
‘‘I don’t think I’d have a huge amount in common with Robert if I met him at a dinner party,’’ Bonneville said. ‘‘But I like the guy. I like the fact that while he does bluster and he’s pompous sometimes, and he makes mistakes, there’s a decency and a love for his family underneath it all.’’
Coinciding with his ‘‘Downton’’ duties, Bonneville also played the addled Head of Deliverance for the Olympics commission in ‘‘Twenty Twelve,’’ a riotous BBC miniseries that spoofed preparations for the London Olympics.
‘‘There are people who think I’ve been doing nothing for 25 years, and then suddenly I get this role on ‘Downton Abbey,’ ’’ Bonneville said with a laugh. ‘‘But I’ve had a really lovely time for 25 years. I’ve played everything from Shakespeare to sitcoms to period dramas to modern serial killers. I consider myself a character actor, and I do love playing different instruments in the orchestra when I get the chance.’’