“Doctor Who,” whose fans gleefully obsess over 37 seasons (now 11 in the modern reboot) of internal history, tends to be a secretive enterprise. Few details have leaked about Mr. Chibnall’s plans, and the premiere screener carried an exhaustive no-spoilers plea: Don’t describe the monsters; don’t say how the Doctor arrives on the scene; don’t say where; don’t say when; don’t say who.

In that spirit, what we can say is that Mr. Chibnall clears the decks. He introduces not just Ms. Whittaker (she replaces Peter Capaldi, the Doctor in the last three seasons) but also a diverse new set of potential traveling companions, one portrayed by Bradley Walsh, who played the Jerry Orbach role on “Law & Order: U.K.” There is, in comparison to recent seasons, scant reference to the show’s mythology, as if Mr. Chibnall is consciously distancing himself from it. The Tardis, the Doctor’s time-and-space ship disguised as a police box, does not appear, and there is, for all intents and purposes, no travel in either time or space.

Beyond any momentary quirks, though, there are deeper changes in style and spirit that are likely to be more permanent. Mr. Moffat’s “Doctor Who” was like an hour spent hanging out with clever undergraduates whose imaginations were on overdrive, saturated in both canonical and pop culture and enamored of wordplay and brain teasers. It was frosted, sometimes too heavily, with moral dilemmas, light conundrums and the kind of romanticism associated with ancient British universities. It could leave you cold or drive you crazy, but there wasn’t much else like it on television.

In Mr. Chibnall’s debut, words and ideas no longer have pride of place — the game playing is gone, along with the sharply morbid sense of humor. This “Doctor Who” feels like a lot of other TV shows, not just in its writing but in its pacing, its cinematography, its use of music. When the scary monsters appear, you could be watching any other well-made but conventional science-fiction or horror show. Or a police procedural, for that matter. Everything about the show is more ordinary, which may have to do with levels of inventiveness but also feels like a choice. Mr. Chibnall has eased off the throttle, lowering the sensations per minute.

Within that context, Ms. Whittaker — who was terrific as a bereaved, angry mother on Mr. Chibnall’s “Broadchurch” — performs gamely, if not yet distinctively, as the 2,000-year-old Time Lord. It’s far too early to tell what kind of stamp she might put on the character, and in the premiere she sometimes seems to be doing an imitation of Mr. Capaldi or his predecessor Matt Smith — one thing Mr. Chibnall has carried over from Mr. Moffat is the Doctor’s clipped, telegraphic dialogue in moments of duress.