With all of the (frequently quite poor) buzz about the arrival this summer of “The Dark Tower” and “The Mist,” “Mr. Mercedes” might be the Stephen King adaptation that has slipped under the radar.  And that’s a shame, because the pilot episode suggests it might be one of the best King adaptations ever.  I’d rate it a 9 out of 10.

It really is that good.  The show’s first episode begins what looks to be an intelligent horror-thriller that is surprisingly faithful to King’s outstanding novel.  David E. Kelley’s script is excellent.  After a brutal prologues that sets its plot in motion, the story proceeds with three-dimensional, likable characters who are well played by their performers — especially Brendan Gleeson in the role of the grumpy, retired-cop anti-hero who is harassed by a mass murderer.  (Yes, that is indeed the Dad from 2002’s “28 Days Later.”)  Gleeson is just great — even though I found myself wondering why a retired Chicago cop should have a heavy U.K. accent.

The script even surprises us by being incongruously sweet during its odder moments.  Like its source material, the show effortlessly sets up characters that are easy to like.  (An exchange between Gleeson some kids playing hockey outside his house, for example, was truly inspired.)

The story’s plot-driving horror elements are disturbing, too — both in terms of its grisly violence and its sexual taboos.  This is not a show for the faint of heart.

This also seems like it could be a King adaptation that could easily appeal to people outside his usual fanbase.  There are no supernatural elements to this story, or any tangible connections to King’s sprawling, interconnected “Dark Tower” multi-verse.  (The original novel seemed to show us King trying his hand at a Thomas Harris-type serial killer tale.)

The only reservation I might have about “Mr. Mercedes” is what I am guessing about its pace.  The original novel was quite slow, despite being an engaging read.  After its gut-wrenching mass murder is depicted in graphic detail, the plot moves forward rather lethargically.  The one-hour pilot episode here seemed to mirror that, in its apparent loyalty to its source material.  I predict that viewers turning to “Mr. Mercedes” for a fast-paced horror tale will be disappointed.

I think that’s probably a subjective quibble on my part, though.  I’d still enthusiastically recommend this.