There’s much to admire in “Servant” — for instance, the show’s painterly compositions, if at times underlit, isolate Free’s character in the far background, as if to say that her soft-spoken, perhaps malignant caretaker character has the ability to literally blend into the background. Ambrose, a welcome presence underseen on big-ticket television since the “Six Feet Under” finale in 2005, makes big and risky choices in constructing her character. She combines brittleness with a bitter sense of humor such that our understanding of Dorothy evolves over the series’s run. As we learn more about her and Sean’s marriage (one in which he, a chef, is often physically absent and yet more frequently disengaged), we shift, eventually, from seeing her as the source of tension to someone bearing its brunt.

And yet for all this, and for all that “Servant” is the most watchable show yet in Apple’s vexed rollout, the series’ somewhat loopy pacing is punishing. Leanne seems as the show runs on to represent far less than meets the eye; episode after episode unfolds without her doing much of anything but seeming threatening in her inaction. (We know she’s going to have to do something eventually, but the wait grows less tantalizing than stultifying.) And to get to a new understanding of Dorothy, one has to trudge fairly deep into the series’s run, long after some viewers may have written her off. And Sean’s willingness to keep her in the dark comes to read less as benevolence than a somewhat uninteresting, uncomplicated sort of villainy. Their behavior raises the question of whether these two can have credibly loved one another in the first place — a twist this story can’t bear. If they are content to torment each other and themselves unremittingly — if, in other words, they truly do not care about each other — then why should we? “Servant” is fascinating to look at and, at first, contemplate. But its slithering, reversing structure elides the fact that it must move the plot forward only infinitesimally each episode in order to conserve it, and that this is a shortish feature in the costume of a ten-episode drama. That’s its biggest, and least welcome, twist of all.