I remember thinking last year that the highly praised drama “Downton Abbey” had tuckered itself out. Season 4 still had all the ingredients that made the miniseries an international hit: the semi-tragic and well-to-do Grantham family in their early 20th century manse, their semi-tragic and put-upon servants, the sly zingers delivered by imperious Maggie Smith as the dowager countess (sample: “There’s nothing simpler than avoiding people you don’t like. Avoiding one’s friends, that’s the real test.”).

Yet the plotlines were drab and disappointing. A promised romance between Grantham cousin Rose and an African-American jazz singer fizzled out. And the rape of maidservant Anna took the show out of the category of escapist costume drama and shocked viewers. “We writhed in our sofas, disbelieving and uncomfortable,” wrote Katy Rink in London’s Daily Telegraph.

And now the show is back for Season 5 (9 p.m. Sundays on PBS, starting Jan. 4).

To watch or not to watch, that is the question for any fan of a middle-aged series that appears to have lost its initial charm. But in the best tradition of British stiff upper lipedness, I watched the first two new episodes.

I admit I fell asleep for a spell early on, which never bodes well. But can you blame me? Dutiful characters dutifully displayed their personality traits: The Earl was still stuffy, Cora was wimpy, Carson the butler was curmudgeonly, Bates the butler was boring. ZZZZ.

But after a 10-minute nap, I awoke to a show that slowly began gathering strength, pushing its predictable characters into unpredictable situations.

Nervous lady’s maid Baxter confesses to Lady Cora about a secret in her past. Sounding rather like Sarah Koenig, host of the true crime podcast “Serial,” Cora is grateful for the info but observes: “There is missing information.” Perhaps an investigation will lend some much-needed edge to the simpering Cora.

Widowed daughter Mary is going to audition a lover with SEX IN A HOTEL ROOM after she dryly (or wryly?) tells him, “I do love you in my cold and unfeeling way.”

Feisty schoolmarm Miss Bunting shares her Marxist views with the Granthams, which seems to awaken the firebrand within chauffeur-turned-aristocratic-son-in-law-turned-widower Tom.

Best of all, family pet Isis, the Labrador from the opening credits, pops up in various scenes: rescued from the fire (oh, did I forget to mention the fire?) and flirted with by a visiting art scholar, though his real interest could be … Cora?

“Downton Abbey,” I daresay you have unjumped the shark.

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