San Francisco — There will be no spoilers in this review of the new season of “Downton Abbey,” premiering tonight on PBS — not just because I wouldn’t want to ruin the pleasure of watching the series, but also because writer-creator Julian Fellowes supplies more than enough spoilers in the script.

Now in its fourth season, “Downton” continues with much of what has made it wonderful and even more of what makes it maddening. Fellowes never met a cliche he couldn’t repurpose to move the upstairs-downstairs story of the residents of a great house in Yorkshire who are reacting to, and in some cases, resisting the social changes that upended England after World War I.

The year is 1922 and the old pile is gloomy, still in the shadow of the death of Matthew Crawley (Dan Stevens) at the end of last season. His mother, Isobel (Penelope Wilton), and widow, Lady Mary (Michelle Dockery), appear all but broken by their shared loss. Mary is so consumed by grief, she can’t bring herself to be much of a mother to her infant son, George.

Her father, Robert, the Earl of Grantham (Hugh Bonneville), and her late sister’s husband, Tom (Allen Leech), are struggling to maintain the estate’s fiscal stability. Robert’s American wife, Lady Cora (Elizabeth McGovern), smiles indulgently at everyone, and his mother, the Dowager Countess (Maggie Smith), continues to make withering pronouncements on everyone’s behavior.

The economic changes in postwar England will bring a new character to the story, Charles Blake (Julian Ovenden), assigned by Lloyd George’s government to assess the stability of old family manses to determine which will make it on their own and which should be broken up. Blake and Lady Mary clash from the outset, and you’d have to be comatose not to get the telegraphed message in their overstated iciness.

Other new characters include Dame Harriet Walter as Lady Shackleton, in a small role, so far, and Dame Kiri Te Kanawa in a cameo as Australian singer Nellie Melba. She’s a New Zealander, of course, so close enough.

Tom Cullen shows up in what appears to be a larger role of Lord Gillingham, an old family friend who played with Lady Mary when they were both children. Also on hand is his valet, Green (Nigel Harman), who riles up the downstairs staff with an abundance of overstated charm.

Although there’s a critical event in the life of a major downstairs character that you won’t see coming, there are plenty of other occurrences that announce their imminent arrival with all the subtlety of an out-of-control train. These will involve romantic events in the lives of Mary’s sister Lady Edith (Laura Carmichael) and the half-baked Lady Rose MacClare (Lily James), career options for Alfred (Matt Milne), and scullery maid Daisy’s (Sophie McShera) obsessive crush on Alfred.

“Downton” is hardly the first TV series to telegraph plot developments by milking cliches, but the script weaknesses do a disservice to both the better moments in the script and to the cast. This is especially evident in Dockery’s wraithlike performance in the early episodes of the season. Yes, her grief is palpable, but the usually excellent Dockery walks around as if her entire body has been Botoxed and she can only speak in a monotone, as if she’s doing an impersonation of actress Gale Sondergaard in some ’40s noir spoof.

Fellowes has created great characters, but as a writer, he fails to listen to them and pushes them around with abandon thinking he’s advancing the story. But the story is the characters, and many of them deserve better.

If this were a minor blip in “Downton,” it could be overlooked, but it keeps the series from being as good as it used to be and from what we want it to be. Telegraphing makes events seem inauthentic, manipulative. That said, when legitimate character-based emotional moments are permitted, they hit with a bang and we love these characters all over again.

The series intelligently probes social changes in the early 1920s. We’ve already been hooked by how much women’s roles in society are expanding in the postwar years. In season four, the issue of race is woven into the story with an African American jazz singer, Jack Ross (Gary Carr), based on the real-life Leslie “Hutch” Hutchinson. We see not only how the upstairs crowd reacts to an African American at Downton, but the staff as well.

Despite the pluses and minuses of the script, the cast generally delivers the goods, especially Phyllis Logan as housekeeper Mrs. Hughes, Joanne Froggatt as lady’s maid Anna Bates, and Jim Carter as Carson, the overseer of the household staff. Brendan Coyle as Bates, Robert’s valet, and Rob-James Collier as the ever-scheming under-butler Barrow, are, like Dockery, sometimes done in by the script weaknesses. Wilton more capably acts her way out of the corners into which the character of Mrs. Crawley is painted.